Removes extra log_env() call
Removes extra log_env() call

Don't print all environment variables for every single cmd() call, refs:
https://github.com/kivy/buildozer/pull/802/files#r261844323
Leaves only one `log_env()` call on command failed.

rnixx/buildozer,rnixx/buildozer,kivy/buildozer,rnixx/buildozer,kivy/buildozer,rnixx/buildozer,kivy/buildozer,kivy/buildozer