Fix the problem when parse config file
Fix the problem when parse config file

Mistral cannot parse configure file from command line
like this:
--config-file="/path/to/config_file"

So update the code to recognize configure file rightly.

Change-Id: I9f3c23d0437578c9714019c480785198c940d181
Closes-Bug: #1552146

StackStorm/mistral,openstack/mistral,StackStorm/mistral,openstack/mistral