Fix for possible nullpointer reported in issue 123

src/com/gitblit/GitFilter.java

@@ -101,11 +101,13 @@ public class GitFilter extends AccessRestrictionFilter {
 	 */
 	@Override
 	protected boolean isActionAllowed(RepositoryModel repository, String action) {
-		if (action.equals(gitReceivePack)) {
-			// Push request
-			if (!repository.isBare) {
-				logger.warn("Gitblit does not allow pushes to repositories with a working copy");
-				return false;
+		if (!StringUtils.isEmpty(action)) {
+			if (action.equals(gitReceivePack)) {
+				// Push request
+				if (!repository.isBare) {
+					logger.warn("Gitblit does not allow pushes to repositories with a working copy");
+					return false;
+				}
 			}
 		}
 		return true;