Use preg_replace instead of escape (#6575)

Escape broke auto matching fields use preg_replace instead.

core/users/user_imports.php

@@ -167,7 +167,7 @@
 			//loop through user columns
 			$x = 0;
 			foreach ($line_fields as $line_field) {
-				$line_field = trim(escape(trim($line_field)), $enclosure);
+				$line_field = preg_replace('#[^a-zA-Z0-9_]#', '', $line_field);
 				echo "<tr>\n";
 				echo "	<td width='30%' class='vncell' valign='top' align='left' nowrap='nowrap'>\n";
 				//echo "    ".$text['label-zzz']."\n";