add third_party/drmemory to .gitignore and remove valgrind.tmp since obsolete

Review URL: http://codereview.chromium.org/6283013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72540 0039d316-1c4b-4281-b951-d872f2087c98

.gitignore

@@ -75,6 +75,7 @@ v8.log
 /third_party/cros
 /third_party/cygwin
 /third_party/directxsdk
+/third_party/drmemory
 /third_party/flac
 /third_party/ffmpeg
 /third_party/gles2_conform
@@ -119,7 +120,6 @@ v8.log
 /tools/page_cycler/acid3
 /tools/tryserver
 /v8
-/valgrind.tmp
 /webkit/Debug
 /webkit/Release
 /webkit/data/bmp_decoder