Only unlock config if we did lock it

Only unlock config if we did lock it

We only acquired a config lock if it was not shared in order
to have lock-free reads. Hence, only release the config lock
if we actually acquired it.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Niklas Hambuechen <niklash@google.com>

Cherry-picked-from: 35056743
Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Hrvoje Ribicic <riba@google.com>