x/build: bot netbsd-arm-bsiegert reported as broken

[gopherbot]

The bot netbsd-arm-bsiegert has been reported as broken. It is currently in "dead" state. Please work to resolve the issue.

@golang/netbsd
@golang/arm

— watchflakes

[bsiegert]

Rebooted the machine. It's back now.

[dmitshur]

The two builders visible at https://ci.chromium.org/ui/p/golang/builders/ci/gotip-netbsd-arm are currently missing. The last incomplete build was yesterday, https://ci.chromium.org/b/8708470930646754817.