Remove pbr warnerrors in favor of sphinx check
This change removes the now unused "warnerrors" setting,
which is replaced by "warning-is-error" in sphinx
releases >= 1.5 [1].
[1] http://lists.openstack.org/pipermail/openstack-dev/
2017-March/113085.html
Change-Id: I59291198f7a216df2f5e5beb2915f48e5a26bd89
Vu Cong Tuan
6 years ago