Don't incorrectly change permissions on link target in SetPermissionsOfLink in unix fs code. Just don't do anything for changes targetting links. b=457487 r=smichaud sr=dougt

xpcom/io/nsLocalFileUnix.cpp

@@ -1086,7 +1086,9 @@ nsLocalFile::SetPermissions(PRUint32 aPermissions)
 NS_IMETHODIMP
 nsLocalFile::SetPermissionsOfLink(PRUint32 aPermissions)
 {
-    return SetPermissions(aPermissions);
+    // There isn't a consistent mechanism for doing this on UNIX platforms. We
+    // might want to carefully implement this in the future though.
+    return NS_ERROR_NOT_IMPLEMENTED;
 }
 
 NS_IMETHODIMP