vm.py: increase the SSH connection timeout for VMs
vm.py: increase the SSH connection timeout for VMs

BUG=chromium:341658
TEST=unittest

Change-Id: Ic109917f04e43818f170f7dbb9eb82d4d54be4fc
Reviewed-on: https://chromium-review.googlesource.com/185263
Reviewed-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Commit-Queue: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Tested-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Reviewed-by: Chris Sosa <959d3d631fb6f17f1b07f751372041a1edb210d1@chromium.org>
Reviewed-by: Don Garrett <546ec366615570e68497e3c5df9092106a9808f4@chromium.org>

bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite