Increase the default pip socket timeout

pip's default timeout of 15 seconds doesn't seem to be high enough
causing us to intermittently fail getting the pypi index. Increasing
the timeout to 60 in an attempt to make it less likely to hit the
problem.

Change-Id: Ifd4689283e53d6afb7a76b480e004cdde3b302f6
Related-Bug: #1272417

modules/jenkins/files/slave_scripts/select-mirror.sh

@@ -44,6 +44,7 @@ EOF
     cat <<EOF > ~/.pip/pip.conf
 [global]
 index-url = http://pypi.openstack.org/openstack
+timeout = 60
 EOF
 else
     echo "$org/$project will not use the internal openstack pypi mirror"