Added a check for the existence of the request object

create_request returns false if validations fail or it returns
the request object itself.
Therefore when validations fail, the value of request is false
which causes the crash.

https://bugzilla.redhat.com/show_bug.cgi?id=1095457
https://bugzilla.redhat.com/show_bug.cgi?id=1138397
Merge pull request #661 from AparnaKarve/bz1095457_create_catalog_item

Fixed crash when validations fail while creating a catalog item