osd/ReplicatedPG.h: init flushed_version in FlushOp ctor

Fix for:

CID 1160851 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
 uninit_member: Non-static class member flushed_version is not
 initialized in this constructor nor in any functions that it calls.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>

Author: dalgaaf

src/osd/ReplicatedPG.h

@@ -254,7 +254,7 @@ class ReplicatedPG : public PG, public PGBackend::Listener {
     Context *on_flush;          ///< callback, may be null
 
     FlushOp()
-      : objecter_tid(0), rval(0),
+      : flushed_version(0), objecter_tid(0), rval(0),
 	blocking(false), removal(false),
 	on_flush(NULL) {}
     ~FlushOp() { assert(!on_flush); }