internal/mod/modload: remove debugging panic with sprintf
I introduced this code two days ago in https://cuelang.org/cl/1195701
and while developing, I had used Sprintf to inspect error values
and panic to loudly surface when they happened in our test suite.
Unfortunately, I forgot the panic and it made it past code review too.
Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I881d2e6ca2979470d7253b2bab0625644829975e
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1195847
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Rustam Abdullaev <rustam@cue.works>