MT#62020 DSPath: prevent retrieve_key_from_non_hash for undef values

Change-Id: I24291f93fb4a38b1f18fd8851f34c0a268c8ccbf
(cherry picked from commit fd292b2cf0)

lib/NGCP/BulkProcessor/DSPath.pm

@@ -99,12 +99,14 @@ sub get {
 
 	# check if last element is reached
 	if ($rest) {
-		if (defined $value and (reftype $value eq 'HASH' or blessed $value)) {
+		if (defined $value) {
+			if (reftype $value eq 'HASH' or blessed $value) {
 				$value = $self->get($rest,$value);
 			} else {
 				$self->{callbacks}->{retrieve_key_from_non_hash}->($data, $key, $index, $value, $rest);
 			}
 		}
+	}
 
 	return $value;
 }