[CORD-2799] Print errors in the logs

Change-Id: Ida468c440a8b8e76eeb7acd54699c440a14b5887
diff --git a/src/web_server/main.py b/src/web_server/main.py
index 632b943..4483053 100644
--- a/src/web_server/main.py
+++ b/src/web_server/main.py
@@ -44,7 +44,9 @@
     def errorCallback(self, failure, request):
         request.setResponseCode(500)
         try:
-            return failure.getErrorMessage()
+            f = failure.getErrorMessage()
+            print "[XOS-TOSCA] Error while loading TOSCA: \n\n", f
+            return f
         except:
             print failure
             return "Internal server error, please report this along with the failed recipe."