fixing sensu check name for glance api check

Both nova and glance sensu_checks had inadvertently been given the same name causing the generated json file for the "check-nova-api" to contain glance's api check configuration, as it would overwrite the previously configured nova-api configuration. 

This commit makes glance's sensu check properly write out its own "check-glance-api.json" file and resolves the issue of incorrectly overwriting the nova-api-check.