Fixed following SonarQube issues:

1. Boolean checks should not be inverted.
2. The comma operator should not be used.
3. Arguments to built-in functions should match documented types.
4. Redundant pairs of parentheses should be removed.
5. A conditionally executed single line should be denoted by indentation, 
6. A while loop should be used instead of a 'for' loop.

web/pgadmin/tools/backup/static/js/backup.js

@@ -210,7 +210,7 @@ define([
       type: 'int',
       deps: ['format'],
       disabled: function(m) {
-        return !(m.get('format') === 'directory');
+        return (m.get('format') !== 'directory');
       },
       visible: function(m) {
         if (!_.isUndefined(m.get('type')) && m.get('type') === 'server')