test/librados: Initializing left members from aio.cc

test/librados: Initializing left members from aio.cc

Fixes the coverity Issue:

** 1322815 Uninitialized pointer field
CID 1322815 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member m_sem is not initialized
in this constructor nor in any functions that it calls.

** 1322816 Uninitialized pointer field
CID 1322816 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member m_sem is not initialized
in this constructor nor in any functions that it calls.

** 1322817 Uninitialized pointer field
CID 1322817 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member m_sem is not initialized
in this constructor nor in any functions that it calls.

Signed-off-by: Amit Kumar amitkuma@redhat.com