b4-wrapper-poky.py: send changes to .b4-config to the poky mailing list

b4-wrapper-poky.py: send changes to .b4-config to the poky mailing list

Both OE-Core and poky git repos have a .b4-config, both at the same
location and both different.

Therefore, changes made to .b4-config for OE-Core need to be sent to the
OE-Core mailing list and changes made to .b4-config for poky sent to the
poky mailing list.

Changes made to OE-Core's .b4-config can only be made from a vanilla
OE-Core git repo, not from poky git repo. With the current content of
OE-Core's .b4-config, b4-wrapper-poky.py script is NOT called to figure
out where to send patches, b4 gets it from the hardcoded value in
send-series-to.

Thus, we can say that if b4-wrapper-poky.py detects changes for
.b4-config, those changes are for poky since this script wouldn't be run
by b4 outside of poky git repo.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>