Catch connection.Error in WifiPreTest.setup_openwrt_connection() am: a6dfa1c1e1

Original change: https://android-review.googlesource.com/c/platform/tools/test/connectivity/+/3302838

Change-Id: I764ce41713aa55a09e301af7660523ca7cbc3e7e
Signed-off-by: Automerger Merge Worker <[email protected]>