Encode result.stdout and stderr to use them in tests
Encode result.stdout and stderr to use them in tests

By default Fabric return Result object where the Result.stdout and
Result.stderr are stored depend on python version (in python2 is
unicode string, in python3 it is bytearray). To Correctly print stdout
or stderr the we encode string to string with encoding utf-8.

scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests