Revert "CPU Optimized the functions."

This reverts commit d43de8790be2b0485666a65af91d45787fa7a78f.
shared_cache: Used Ceph::shared_ptr and ceph::weak_ptr

Since std::tr1::shared_ptr and std::tr1::weak_ptr won't be available for
all the platforms. We are using ceph::shared_ptr and ceph::weak_ptr

Signed-off-by: Somnath Roy <somnath.roy@sandisk.com>
MOSDOp, MOSDOpReply: Returning the class/structures by const reference

Signed-off-by: Somnath Roy <somnath.roy@sandisk.com>
MOSDOpReply: Used copy construcor in the initializer list instead of
assignment operator in the constructor body.

Signed-off-by: Somnath Roy <somnath.roy@sandisk.com>
Pipe: Used reference for getting rid of unnecessary bufferlist copy

Signed-off-by: Somnath Roy <somnath.roy@sandisk.com>