Fix - do not try to process an empty common string, make more valid urls

Before: index.php?&server=1
After: index.php?server=1

Using move and go to database feature

Signed-off-by: William Desportes <williamdes@wdes.fr>

js/src/common.js

@@ -88,7 +88,7 @@ var CommonParams = (function () {
             var sep = (typeof separator !== 'undefined') ? separator : '?';
             var common = this.get('common_query');
             var argsep = CommonParams.get('arg_separator');
-            if (typeof common === 'string') {
+            if (typeof common === 'string' && common.length > 0) {
                 // If the last char is the separator, do not add it
                 // Else add it
                 common = common.substr(common.length - 1, common.length) === argsep ? common : common + argsep;