Fix file.copy recipe_module to not fail if files are already equal.

scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json

Index: scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json
diff --git a/scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json b/scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json
index 3b56605913f8d2a63278396b8d8c5be82e589f7a..c5fa14a32ec83d026f08b9879967aa4339584998 100644
--- a/scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json
+++ b/scripts/slave/recipes/v8/auto_roll_release_process.expected/recent_lkgr.json
@@ -114,7 +114,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\nimport shutil\nimport sys\n# Apparently, shutil.copy fails if files are binary-equal on *nix OSes.\n# See http://crbug.com/636168#c8.\nif hasattr(shutil, '_samefile'):\n  if shutil._samefile(sys.argv[1], sys.argv[2]):\n    sys.exit(0)\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/refs_heads_lkgr.log",
       "/path/to/tmp/"
     ],
@@ -201,7 +201,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\nimport shutil\nimport sys\n# Apparently, shutil.copy fails if files are binary-equal on *nix OSes.\n# See http://crbug.com/636168#c8.\nif hasattr(shutil, '_samefile'):\n  if shutil._samefile(sys.argv[1], sys.argv[2]):\n    sys.exit(0)\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/timestamp.txt",
       "/path/to/tmp/"
     ],