GinkgoRecover() in goroutines

This is the only instance I have found, but we should probably
add these in a consistent place.

While these functions look safe, they actually run inside of a goroutine
because of the testhttp package test server implementation. Recovering
makes our errors slightly nicer.
Allow 'cf unset-env' to remove the last env var an app has

Apparently we were a little too defensive when we changed this code to
only sometimes send environment variables. When the env var map has
zero entries, we may want to send that to CC, eg: when an app has
a single env var and we want to delete it

[#Finishes #68879028] #134
go fmt