Remove unnecessary cleverness in stripping off the hyphen for mysql

version checks that was causing problems in the case where there's no
hyphen.  version_compare handles hypens fine.

installer/installer.php

@@ -110,9 +110,7 @@ static function verify_mysql_version($config) {
 
   static function mysql_version($config) {
     $result = mysql_query("SHOW VARIABLES WHERE variable_name = \"version\"");
-    $row = mysql_fetch_object($result);
-    $version = substr($row->Value, 0, strpos($row->Value, "-"));
-    return $version;
+    return $row->Value;
   }
 
   static function db_empty($config) {