[now-cli] Don't print "Error starting dev server" message by default (#4172)
[now-cli] Don't print "Error starting dev server" message by default (#4172)

It's not useful information and distracts from whatever the actual error
message was from the dev server, which is what the user is actually
interested in.
zeit/now-cli,zeit/now-cli,zeit/now-cli,zeit/now-cli,zeit/now-cli,zeit/now-cli,zeit/now-cli