Fixed Skylark python rule under OS X

find on OS X does not support not provided a path argument. Python
example was failing because of it.

--
MOS_MIGRATED_REVID=89287951

tools/build_rules/py_rules.bzl

diff --git a/tools/build_rules/py_rules.bzl b/tools/build_rules/py_rules.bzl
index ddd43df..8573381 100644
--- a/tools/build_rules/py_rules.bzl
+++ b/tools/build_rules/py_rules.bzl
@@ -62,9 +62,9 @@
               " cp %s %s/main.zip && " % (deploy_zip_nomain.path, outdir) +
               " (cd %s && " % outdir +
               "  mkdir -p %s && " % " ".join(dirs) +
-              "  find -type d -exec touch -t 198001010000 '{}'/__init__.py ';' && " +
+              "  find . -type d -exec touch -t 198001010000 '{}'/__init__.py ';' && " +
               "  chmod +w main.zip && " +
-              "  %s -qR main.zip $(find -type f ) ) && " % (ZIP_PATH) +
+              "  %s -qR main.zip $(find . -type f ) ) && " % (ZIP_PATH) +
               " mv %s/main.zip %s " % (outdir, deploy_zip.path))
 
   ctx.action(