commitlog: do not wait on pending operations for batch mode
commitlog: do not wait on pending operations for batch mode

This was explicitly mentioned in my set as gone in one of the versions.
Somehow it came back in the final version - sorry about that.

Signed-off-by: Glauber Costa <7ba9037b0dd006f9408bd45b94707becd5cd4e87@scylladb.com>
Message-Id: <2a0eba28cd74267d1a1fdcf1aef2901cc74ffc9f.1477059963.git.7ba9037b0dd006f9408bd45b94707becd5cd4e87@scylladb.com>

raphaelsc/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,raphaelsc/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,raphaelsc/scylla