connman: include an empty resolv.conf

Ensure that an empty resolv.conf exists before connman writes to it. This way
we have it in place in the read-only /, and we can bind mount over it.

JIRA: SB-1386

Signed-off-by: Christopher Larson <kergoth@gmail.com>
volatile-binds: bind mount /etc/resolv.conf

JIRA: SB-1386

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Merge pull request #3 from kergoth/writable-resolv-conf

Make /etc/resolv.conf writable for read-only-rootfs