LAPD: Free resume/re-establishment msgb if it carries no content

lapdm.c takes the re-establishment message and forwards it to lapd_core.c,
so we can assume that msgb is set at primitive. In case there is data in
the re-establishment msg, it is moved into send_buffer. In case of no
data (0 length), it must be freed.

Fixes an issue spotted by Coverity Scan.
1 file changed