Output stdout and stderr when nailgun fails to connect (#5892)
Output stdout and stderr when nailgun fails to connect (#5892)

Fixes #5853
benjyw/pants,benjyw/pants,wisechengyi/pants,twitter/pants,twitter/pants,baroquebobcat/pants,jsirois/pants,wisechengyi/pants,baroquebobcat/pants,wisechengyi/pants,tdyas/pants,wisechengyi/pants,tdyas/pants,wisechengyi/pants,twitter/pants,wisechengyi/pants,twitter/pants,tdyas/pants,tdyas/pants,pantsbuild/pants,twitter/pants,jsirois/pants,baroquebobcat/pants,benjyw/pants,pantsbuild/pants,baroquebobcat/pants,twitter/pants,twitter/pants,tdyas/pants,wisechengyi/pants,baroquebobcat/pants,twitter/pants,tdyas/pants,pantsbuild/pants,jsirois/pants,pantsbuild/pants,wisechengyi/pants,tdyas/pants,benjyw/pants,twitter/pants,baroquebobcat/pants,pantsbuild/pants,baroquebobcat/pants,baroquebobcat/pants,baroquebobcat/pants,pantsbuild/pants,benjyw/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,tdyas/pants,wisechengyi/pants,tdyas/pants