skipif decorator logs wrong message

When multiple SkipIf decorators are used and the test is skipped due to one of them, the message that is logged is the message of the first SkipIf decorator (even if the condition of that decorator is false).

Example:

$ export TARGET_FILESYSTEM="s3"
$ run-tests.py metadata/test_hms_integration.py -k test_hive_db_hive_table_add_partition

This will output "Hive not tested with Isilon" to tests/results/TEST-impala-serial.log.
Changing the order of the decorators of TestHmsIntegration in metadata/test_hms_integration.py changes the log message.