(PUP-3151) Removed newline from host_entry test fixture

This commit removes the newline character from the end of the host_entry
method in the acceptance test ExternalCertFixtures.  The presence of this
character was causing the jetty_external_root_ca.rb test, when run on
Debian, to not properly set the needed hostname entry into the
/etc/hosts file.
Merge pull request #1 from camlow325/waynr/puppet/quickfix/external_ca_test_fix

(PUP-3151) Removed newline from host_entry test fixture