schedule_suite.sh: include install task in all jobs

This is probably temporary.  It's simpler than adding the task to every
job in the suite.  We'll want to do that later when we want to test
alternative install methods (like ceph-deploy's install function).

Signed-off-by: Sage Weil <sage@inktank.com>
install: clean up flavor, distro, arch detection

Signed-off-by: Sage Weil <sage@inktank.com>