site/common-linux: centralize bash configure vars

site/common-linux: centralize bash configure vars

If the other site files are accurate, almost all of the bash vars
are universal across Linux.

Did this to fix bash on x86_64. Also bump bash PRs to help track
breakage later.

Signed-off-by: Michael Smith <msmith@cbnco.com>
Acked-by: Tom Rini <trini@embeddedalley.com>
Acked-by: Khem Raj <raj.khem@gmail.com>