librados: Translate operation flags from C APIs

librados: Translate operation flags from C APIs

The operation flags in the public C API are a distinct enum
and need to be translated to Ceph OSD flags, like as happens in
the C++ API. It seems like the C enum and the C++ enum consciously
use the same values, so I reused the C++ translation function.

Signed-off-by: Matthew Richards <mattjrichards@gmail.com>
(cherry picked from commit 49d114f1fff90e5c0f206725a5eb82c0ba329376)

Conflicts:
	src/librados/librados.cc
        comes from lttng tracepoints introduced after firefly