gn bootstrap.py: Fixed attrib error "no_bootstrap"

bootstrap.py:
+ no_bootstrap => no_rebuild

NOTRY=true
R=brettw@chromium.org
BUG=

Review URL: https://codereview.chromium.org/412053004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285603 0039d316-1c4b-4281-b951-d872f2087c98

tools/gn/bootstrap/bootstrap.py

@@ -78,7 +78,7 @@ def main(argv):
       temp_gn = os.path.join(tempdir, 'gn')
       out_gn = os.path.join(build_root, 'gn')
 
-      if options.no_bootstrap:
+      if options.no_rebuild:
         mkdir_p(build_root)
         shutil.copy2(temp_gn, out_gn)
       else: