Fix #635 use mv instead of rename as that does not support cross volume operations

CHANGELOG.md

@@ -3,6 +3,7 @@
 
 1. [](#bugfix)
     * Fixed case where extracting a package would cause an error during rename
+    * Fixed [#635](https://github.com/getgrav/grav/issues/635) use mv instead of rename as that does not support cross volume operations
 
 # v1.1.9
 ## 12/13/2016

system/src/Grav/Common/Filesystem/Folder.php

@@ -340,11 +340,13 @@ abstract class Folder
         // Make sure that path to the target exists before moving.
         self::create(dirname($target));
 
-        // Just rename the directory.
-        $success = @rename($source, $target);
+        error_clear_last();
 
-        if (!$success) {
-            $error = error_get_last();
+        // Just rename the directory.
+        exec("mv $source $target");
+
+        $error = error_get_last();
+        if ($error) {
             throw new \RuntimeException($error['message']);
         }