Enhance the compatibility judgement of INSTALLER
Enhance the compatibility judgement of INSTALLER

When the env INSTALLER_TYPE is None, while the var installer in
dependencies is not None, the current test case should not be run.

Change-Id: If1b67f16f39d5c44b2c3729819dd665faed41b73
Signed-off-by: Linda Wang <81613bebe84fa394bbc7c5cc1c21989c9bff2c52@huawei.com>

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