check,common{rc,preamble}: Decouple init_rc() call from sourcing common/rc

check,common{rc,preamble}: Decouple init_rc() call from sourcing common/rc

Silently executing scripts during sourcing common/rc isn't good practice
and also causes unnecessary script execution. Decouple init_rc() call
and call init_rc() explicitly where required.

Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>