os: call f.Close before t.Fatal to avoid vet unreachable code warnings
Change-Id: Ic3f756ecf9b4fad8fb8c259e7dad6df894863b0e
GitHub-Last-Rev:
303e524029289fb4c0cb114dad7cb03c4fce9637
GitHub-Pull-Request: golang/go#41900
Reviewed-on: https://go-review.googlesource.com/c/go/+/261217
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Trust: Emmanuel Odeke <emm.odeke@gmail.com>