Catch TypeError exceptions in ci/tier_handler.py
Catch TypeError exceptions in ci/tier_handler.py

If INSTALLER_TYPE is unset, is_compatible returns False instead of
raising an ErrorType exception.

Change-Id: I55c219808851907a19e2aa0124eb13d53a5e685d
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

mywulin/functest,mywulin/functest,opnfv/functest,opnfv/functest