Teach build/symlink.py --force to delete directories.

Otherwise os.remove just fails saying it can't delete a directory.

R=dpranke@chromium.org

Review URL: https://codereview.chromium.org/1222573002

Cr-Original-Commit-Position: refs/heads/master@{#337083}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: add100b7cd19ae6caad54ac6c6ed9766b7f1f70b

symlink.py

@@ -9,6 +9,7 @@
 import errno
 import optparse
 import os.path
+import shutil
 import sys
 
 
@@ -29,7 +30,10 @@ def Main(argv):
       os.symlink(s, t)
     except OSError, e:
       if e.errno == errno.EEXIST and options.force:
-        os.remove(t)
+        if os.path.isdir(t):
+          shutil.rmtree(t, ignore_errors=True)
+        else:
+          os.remove(t)
         os.symlink(s, t)
       else:
         raise