Revert "Print error message if rspec execution fails"
Revert "Print error message if rspec execution fails"

This reverts commit edf0d0e55250e7064bc03d7080eb98242c5e1f4f. Rspec does
not differentiate between failing tests and failing to run the tests.

baberthal/guard-rspec,kvokka/guard-rspec,consti/guard-rspec,mes/guard-rspec,guard/guard-rspec