Only warn about tab-indent
Only warn about tab-indent

I noticed this in I21d3c2ad7a020a5ab02dc1ab532feae70b718892 ; if you
have a tab-indent, we don't need to warn that the same line is also
not indented correctly

Change-Id: If0499126fc64861de971f851e2715d4379bd9dee

openstack-dev/bashate,openstack-dev/bashate