pybind/rados: add missing "length" requires for aio_execute()

[tchaikov]

Signed-off-by: Kefu Chai kchai@redhat.com

[tchaikov]

2016-12-10T02:47:57.131 INFO:tasks.workunit.client.0.mira092.stderr:======================================================================
2016-12-10T02:47:57.131 INFO:tasks.workunit.client.0.mira092.stderr:ERROR: test_rados.TestIoctx.test_aio_execute
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:----------------------------------------------------------------------
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:Traceback (most recent call last):
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:  File "/usr/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:    self.test(*self.arg)
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:  File "/home/ubuntu/cephtest/mnt.0/client.0/tmp/test_rados.py", line 840, in test_aio_execute
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:    comp = self.ioctx.aio_execute("foo", "hello", "say_hello", b"", 32, cb, cb)
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:  File "rados.pyx", line 450, in rados.requires.wrapper.validate_func (/home/jenkins-build/build/workspace/ceph-dev-new-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/release/11.0.2-2392-g10834f2/rpm/el7/BUILD/ceph-11.0.2-2392-g10834f2/build/src/pybind/rados/pyrex/rados.c:4203)
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:  File "rados.pyx", line 433, in rados.requires.check_type (/home/jenkins-build/build/workspace/ceph-dev-new-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/release/11.0.2-2392-g10834f2/rpm/el7/BUILD/ceph-11.0.2-2392-g10834f2/build/src/pybind/rados/pyrex/rados.c:3565)
2016-12-10T02:47:57.132 INFO:tasks.workunit.client.0.mira092.stderr:TypeError: oncomplete must be Callable or None

see http://pulpito.ceph.com/kchai-2016-12-10_02:13:38-rados-wip-kefu-testing---basic-mira/621255/

[jdurgin]

lgtm