buildbot_test_toolchains: fix a typo

BUG=none
TEST=it runs with a patch parameter.

Change-Id: I08437d0ec47ef27a3b88930358f3c149fd955cdc
Reviewed-on: https://chrome-internal-review.googlesource.com/227861
Reviewed-by: Han Shen <shenhan@google.com>
Commit-Queue: Yunlian Jiang <yunlian@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
1 file changed