Fix http://b/issue?id=5030894 ('Not working on windows: python gyp_skia')

git-svn-id: http://skia.googlecode.com/svn/trunk@1864 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp_skia b/gyp_skia
index 2a8701f..bf2feba 100755
--- a/gyp_skia
+++ b/gyp_skia
@@ -63,7 +63,7 @@
   # finickyness about the current working directory.
   # See http://b.corp.google.com/issue?id=5019517 ('Linux make build
   # (from out dir) no longer runs skia_gyp correctly')
-  os.chdir(script_dir)
+  os.chdir(os.path.abspath(script_dir))
 
   # This could give false positives since it doesn't actually do real option
   # parsing.  Oh well.