There's a need to keep building images from eol releases. This commit
introduces ability to specify eol release for project and clone to
{release}-eol instead of stable/{release}
Octavia moved to eol, using ocata-eol instead.
Also fixes gates providing ensure-pip role to executor.
Also pins openSUSE image to 15.1
Change-Id: I041033bb6c9cfe193c4bae9a0b6b4028f4602c5f
Signed-off-by: Andrii Ostapenko <andrii.ostapenko@att.com>