sweet: shell-quote environment variable values in -shell log

Currently the environment variable values printed when -shell is passed
aren't shell-quoted. As a result, the command produced by -shell may be
not directly usable in some circumstances. Fix this by running
shellquote.Join on the variable.

Change-Id: I77a136c27cbd31388697bdd54927dd40d40535e5
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/614539
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
1 file changed