common: fix missing include boost/noncopyable.hpp

common: fix missing include boost/noncopyable.hpp

Clang complains:
```
In file included from /home/jenkins/workspace/ceph-master/src/osd/ReplicatedBackend.cc:15:
In file included from /home/jenkins/workspace/ceph-master/src/osd/ReplicatedBackend.h:18:
In file included from /home/jenkins/workspace/ceph-master/src/osd/PGBackend.h:27:
In file included from /home/jenkins/workspace/ceph-master/src/osd/PGTransaction.h:25:
/home/jenkins/workspace/ceph-master/src/common/inline_variant.h:88:64: error: expected class name
struct generic_visitor : boost::static_visitor<Result>, boost::noncopyable
                                                               ^
1 error generated.
gmake[2]: *** [src/osd/CMakeFiles/osd.dir/build.make:141: src/osd/CMakeFiles/osd.dir/ReplicatedBackend.cc.o] Error 1
gmake[2]: *** Waiting for unfinished jobs....
```

Signed-off-by: Willem Jan Withagen <wjw@digiware.nl>