Skip released that are close but not fully EOLd when building wheels

The requirements project is very slow to actually tag branches as EOLd as
that can cause some testing environments and devstack to fail.  For
example if tox.ini refers to a constraints file in git[1].

However building wheels for those releases isn't actually helpful as
they're not chnaging *and* can cause failed runs as pypi etc move on.

This change adds an regex for the closed branches to exclude them from
building.  The regex is a little more complex than the single case
(newton) requires but allows for easier future additions.

[1] http://git.openstack.org/cgit/openstack/nova/tree/tox.ini?h=newton-eol#n12

Change-Id: Ia0c589989cb6e7e81e7b08e39d81dac78c55bf18

roles/build-wheels/files/wheel-build.sh

@@ -13,7 +13,8 @@ mkdir -p ${LOGS}
 rm -rf ${LOGS}/*
 
 # Extract and iterate over all the branch names.
-BRANCHES=`git --git-dir=$WORKING_DIR/.git branch -a | grep '^  stable'`
+BRANCHES=`git --git-dir=$WORKING_DIR/.git branch -a | grep '^  stable' | \
+            grep -Ev '(newton)'`
 for BRANCH in master $BRANCHES; do
     git --git-dir=$WORKING_DIR/.git show $BRANCH:upper-constraints.txt \
         2>/dev/null > /tmp/upper-constraints.txt  || true