Match `stage` for `Deploy Pants Pex Unstable` (#6704)
Match `stage` for `Deploy Pants Pex Unstable` (#6704)

Follow up for #6694 to make travis recognize the added stage.
wisechengyi/pants,twitter/pants,pantsbuild/pants,wisechengyi/pants,tdyas/pants,twitter/pants,tdyas/pants,wisechengyi/pants,jsirois/pants,pantsbuild/pants,tdyas/pants,benjyw/pants,benjyw/pants,twitter/pants,pantsbuild/pants,jsirois/pants,wisechengyi/pants,tdyas/pants,pantsbuild/pants,wisechengyi/pants,wisechengyi/pants,tdyas/pants,twitter/pants,benjyw/pants,tdyas/pants,pantsbuild/pants,twitter/pants,jsirois/pants,benjyw/pants,twitter/pants,wisechengyi/pants,tdyas/pants,tdyas/pants,wisechengyi/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,wisechengyi/pants,benjyw/pants,twitter/pants,tdyas/pants,twitter/pants,twitter/pants,pantsbuild/pants