layers: Remove unneeded layer_common.h

The header only had one include in it.
diff --git a/layers/device_limits.h b/layers/device_limits.h
index 6f11c23..8575b90 100644
--- a/layers/device_limits.h
+++ b/layers/device_limits.h
@@ -23,7 +23,7 @@
  */
 #include "vk_layer.h"
 #include <vector>
-#include "layer_common.h"
+#include "vk_debug_report_lunarg.h"
 
 using namespace std;
 
diff --git a/layers/draw_state.h b/layers/draw_state.h
index ecd9486..1641f8a 100644
--- a/layers/draw_state.h
+++ b/layers/draw_state.h
@@ -23,7 +23,7 @@
  */
 #include "vk_layer.h"
 #include <vector>
-#include "layer_common.h"
+#include "vk_debug_report_lunarg.h"
 
 using namespace std;
 
diff --git a/layers/layer_common.h b/layers/layer_common.h
deleted file mode 100644
index 3e3e916..0000000
--- a/layers/layer_common.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Vulkan
- *
- * Copyright (C) 2014 LunarG, Inc.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
-#include "vk_debug_report_lunarg.h"
-
diff --git a/layers/mem_tracker.h b/layers/mem_tracker.h
index fec008a..5ad0059 100644
--- a/layers/mem_tracker.h
+++ b/layers/mem_tracker.h
@@ -24,7 +24,7 @@
 #pragma once
 #include <vector>
 #include "vk_layer.h"
-#include "layer_common.h"
+#include "vk_debug_report_lunarg.h"
 
 #ifdef __cplusplus
 extern "C" {