QA: Adjust test whether file storage is enabled
QA: Adjust test whether file storage is enabled

This patch fixes the node storage QA, which checked whether
file storage is enabled by looking at the constant
'ENABLE_FILE_STORAGE'. QA should rather retrieve this
information from the QA config.

Signed-off-by: Helga Velroyen <2d0126b1ec6f9ec5cbec4a7012aa14faeaef10f5@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

dimara/ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,bitemyapp/ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,yiannist/ganeti,dimara/ganeti,leshchevds/ganeti,mbakke/ganeti,andir/ganeti,andir/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,leshchevds/ganeti,onponomarev/ganeti,grnet/snf-ganeti,andir/ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti,grnet/snf-ganeti,apyrgio/ganeti,mbakke/ganeti,ganeti/ganeti