Removed lprotobuf error on building

Will need @ctrlaltca to confirm this wont mess anything up. I have
removed a option to se set from the cmake file. This option is not
needed.

Windows users, you will need to run cmake to create the sln again.

common/pb/CMakeLists.txt

@@ -154,9 +154,6 @@ PROTOBUF_GENERATE_CPP(PROTO_SRCS PROTO_HDRS ${PROTO_FILES})
 
 add_library(cockatrice_protocol ${PROTO_SRCS} ${PROTO_HDRS})
 set(cockatrice_protocol_LIBS ${PROTOBUF_LIBRARIES})
-if (MSVC)
-    set(cockatrice_protocol_LIBS ${cockatrice_protocol_LIBS} -lprotobuf)
-endif (MSVC)
 if (UNIX)
     set(cockatrice_protocol_LIBS ${cockatrice_protocol_LIBS} -lpthread)
 endif (UNIX)