cmd/dist: remove unused variables
cmd/dist: remove unused variables

Remove the unused defaultcflags and defaultldflags variables.

Reported by staticcheck.

Change-Id: Icc42f2e670496dbe2ffb26abe25128d8e53e2a6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/321931
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>

CAFxX/go,CAFxX/go,cloudflare/go,cloudflare/go,nawawi/go,CAFxX/go,CAFxX/go,cloudflare/go,nawawi/go,cloudflare/go,nawawi/go,CAFxX/go,golang/go,golang/go,golang/go,golang/go,golang/go,cloudflare/go,cloudflare/go,golang/go,nawawi/go,golang/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,nawawi/go