Fix keystone command man page
Fix keystone command man page

The overline/underline for the title was too short which generated
an error.

Change-Id: I2ba30ff9c819c425d5973c8cf5fd92d5642b5885

ging/python-keystoneclient,klmitch/python-keystoneclient,darren-wang/ksc,ging/python-keystoneclient,jamielennox/python-keystoneclient,alexpilotti/python-keystoneclient,metacloud/python-keystoneclient,sdpp/python-keystoneclient,alexpilotti/python-keystoneclient,darren-wang/ksc,sdpp/python-keystoneclient,jamielennox/python-keystoneclient,Mercador/python-keystoneclient,klmitch/python-keystoneclient,jamielennox/python-keystoneclient,metacloud/python-keystoneclient,magic0704/python-keystoneclient,Mercador/python-keystoneclient,magic0704/python-keystoneclient