Remove v8- prefix of file name in libsampler.

src/libsampler/sampler.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "src/libsampler/v8-sampler.h"
+#include "src/libsampler/sampler.h"
 
 #if V8_OS_POSIX && !V8_OS_CYGWIN
 
 #define USE_SIGNALS
 
 #include <errno.h>
 #include <pthread.h>
 #include <signal.h>
 #include <sys/time.h>
 
@@ skipping 648 matching lines @@
 #endif
     SampleStack(state);
   }
   ResumeThread(profiled_thread);
 }
 
 #endif  // USE_SIGNALS
 
 }  // namespace sampler
 }  // namespace v8