Coding Standards: Fix instances of WordPress.PHP.NoSilencedErrors.Discouraged.

Noteable changes:
- The `magic_quotes_runtime` and `magic_quotes_sybase` settings were removed in PHP 5.4, so no longer need to be set.
- Some functions that use external libraries can generate errors that can't be tested for, so are globally allowed to silence errors.
- Quite a few functions would cause errors if `safe_mode` was set. This setting was removed in PHP 5.4.
- Only a handful of `header()` calls needed corresponding `headers_sent()` checks for unit tests to pass, but more may need to be added as the nightlies builds are tested.

See #46732.


git-svn-id: https://develop.svn.wordpress.org/trunk@45611 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-filesystem-ssh2.php

@@ -484,7 +484,17 @@ class WP_Filesystem_SSH2 extends WP_Filesystem_Base {
 	 * @return bool True on success, false on failure.
 	 */
 	public function move( $source, $destination, $overwrite = false ) {
-		return @ssh2_sftp_rename( $this->sftp_link, $source, $destination );
+		if ( $this->exists( $destination ) ) {
+			if ( $overwrite ) {
+				// We need to remove the destination file before we can rename the source.
+				$this->delete( $destination, false, 'f' );
+			} else {
+				// If we're not overwriting, the rename will fail, so return early.
+				return false;
+			}
+		}
+
+		return ssh2_sftp_rename( $this->sftp_link, $source, $destination );
 	}
 
 	/**
@@ -711,12 +721,12 @@ class WP_Filesystem_SSH2 extends WP_Filesystem_Base {
 			$limit_file = false;
 		}
 
-		if ( ! $this->is_dir( $path ) ) {
+		if ( ! $this->is_dir( $path ) || ! $this->is_readable( $path ) ) {
 			return false;
 		}
 
 		$ret = array();
-		$dir = @dir( $this->sftp_path( $path ) );
+		$dir = dir( $this->sftp_path( $path ) );
 
 		if ( ! $dir ) {
 			return false;