- update to 1.3.7
librtas allocates buffer space (required for RTAS call) in the
RTAS private memory area through sc_get_rmo_buffer() which
internally allocates memory and protects it by acquiring
lock on the allocated memory area.

Locking function :
At present acquire_file_lock() tries to lock the particular
memory area. If the memory area is already locked then it
returns error without retrying.

So when two process executes rtas call simultaneously one fails
with "Unknown librtas I/O" error.

This patch introduces "Wait for lock to be available" instead
of returning with IO error.

- fixed minor memory leak in librtas.so