Plugin not saving values when placed in a folder within /wp-content/plugins

Here is the fixed and modified code which was having the nonce action issue.

<?php
/*
Plugin Name: Test Plugin
Plugin URI: Test
Description: Test
Author: Test
Version: 007
Author URI:
*/

// add all post types
$clinical_post_types = array();
$post_types          = get_post_types();
foreach ( $post_types as $post_type ) {
    $clinical_post_types[] = $post_type;
}

// Meta box
// Add the language metabox on every registered custom post type
function clinical_add_language_metaboxe() {
    global $clinical_post_types;
    foreach ( $clinical_post_types as $post_type ) {
        add_meta_box( 'clinical_meta_box', __( 'Search Engine Optimization', 'clinical' ), 'clinical_meta_custom_box', $post_type, 'normal', 'default' );
    }
}

// The Post's meta fields Metabox
function clinical_meta_custom_box() {
    global $post;

    // Get the meta fields data if its already been entered
    $meta_title       = get_post_meta( $post->ID, '_clinical_meta_title', true );
    $meta_description = get_post_meta( $post->ID, '_clinical_meta_description', true );

    echo '<input type="hidden" name="clinicalmeta_noncename" id="clinicalmeta_noncename" value="' . wp_create_nonce( "clinicalmeta_nonce_action" ) . '" />';

    // Echo out the field
    $html="<p><label for="clinical_meta_title"><strong>" . __( 'Title', 'clinical' ) . '</strong></label></p>';
    $html .= '<p><input type="text" class="regular-text" name="_clinical_meta_title" id="clinical_meta_title" value="' . $meta_title . '" /></p>';
    $html .= '<p><label for="clinical_meta_description"><strong>' . __( 'Description', 'clinical' ) . '</strong></label></p>';
    $html .= '<p><textarea class="large-text" name="_clinical_meta_description" id="clinical_meta_description">' . $meta_description . '</textarea></p>';
    echo $html;
}

// Save the metabox data
function clinical_save_post_meta( $post_id, $post ) {
    global $clinical_post_types;

    $key_title="_clinical_meta_title";
    $key_description = '_clinical_meta_description';

    // if we're not in a clinical-enabled post type, skip.
    if ( in_array( $post->post_type, $clinical_post_types ) ) {
        // return $post;
    }
    // verify this came from our screen and with proper authorization,
    // because save_post can be triggered at other times
    if ( ( empty( $_POST[ $key_title ] ) && empty( $_POST[ $key_description ] ) ) || empty( $_POST['clinicalmeta_noncename'] ) || ( ! wp_verify_nonce( $_POST['clinicalmeta_noncename'], "clinicalmeta_nonce_action" ) ) || ( ! current_user_can( 'edit_post', $post->ID ) ) ) {
        return $post->ID;
    }
    // OK, we're authenticated: we need to find and save the data
    $title       = $_POST[ $key_title ];
    $description = $_POST[ $key_description ];

    // set the post's meta title:
    $updated_title       = update_post_meta( $post->ID, $key_title, $title );
    $updated_description = update_post_meta( $post->ID, $key_description, $description );
    // Delete if blank:
    if ( empty( $title ) ) {
        delete_post_meta( $post->ID, $key_title );
    }
    if ( empty( $description ) ) {
        delete_post_meta( $post->ID, $key_description );
    }
}

// Filters
function clinical_wp_title_filter( $title ) {
    global $post;
    $seo_title = get_post_meta( $post->ID, '_clinical_meta_title', true );
    if ( ! empty( $seo_title ) ) {
        return $seo_title;
    }

    return $title;
}

function clinical_wp_head_action() {
    global $post;
    $seo_description = get_post_meta( $post->ID, '_clinical_meta_description', true );
    if ( ! empty( $seo_description ) ) {
        echo '<!-- Clinical CMS SEO --> <meta name="description" content="' . esc_attr( $seo_description ) . '" /> <!-- END Clinical CMS  SEO -->';
    }
}

// Helpers
// Filters and Hooks
add_action( 'admin_init', 'clinical_add_language_metaboxe' );
add_action( 'save_post', 'clinical_save_post_meta', 1, 2 );
add_filter( 'wp_title', 'clinical_wp_title_filter' );
add_action( 'wp_head', 'clinical_wp_head_action' );