Rename RWLockGeneric to RWLockWinXP to more accurately reflect when it's used.

webrtc/system_wrappers/source/rw_lock.cc

Index: webrtc/system_wrappers/source/rw_lock.cc
diff --git a/webrtc/system_wrappers/source/rw_lock.cc b/webrtc/system_wrappers/source/rw_lock.cc
index ff44896dbe324dd73556504dcff32df0d45445f4..7c77123a0b7eb79aa156174cd79b63322f823718 100644
--- a/webrtc/system_wrappers/source/rw_lock.cc
+++ b/webrtc/system_wrappers/source/rw_lock.cc
@@ -13,8 +13,8 @@
 #include <assert.h>
 
 #if defined(_WIN32)
-#include "webrtc/system_wrappers/source/rw_lock_generic.h"
 #include "webrtc/system_wrappers/source/rw_lock_win.h"
+#include "webrtc/system_wrappers/source/rw_lock_winxp_win.h"
 #else
 #include "webrtc/system_wrappers/source/rw_lock_posix.h"
 #endif
@@ -28,7 +28,7 @@ RWLockWrapper* RWLockWrapper::CreateRWLock() {
   if (lock) {
     return lock;
   }
-  return new RWLockGeneric();
+  return new RWLockWinXP();
 #else
   return RWLockPosix::Create();
 #endif