liblockfile: inherit autotools-brokensep

Seperation of ${B} and ${S} causes a build failure for liblockfile.

The error message is as follows.
make: *** No rule to make target `lockfile.c', needed by `lockfile.o'.  Stop.

Make liblockfile inherit autotools-brokensep to fix this problem.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>