Bug 1526763 - Remove `.encode()` from test_load_non_ascii_textlog_errors (#4617)
Bug 1526763 - Remove `.encode()` from test_load_non_ascii_textlog_errors (#4617)

Since by design `.encode()` returns bytes, whereas the test should be using
a string. The goal of the encode seems to have been to handle unicode
correctly, however that's now achieved via the use of:
`from __future__ import unicode_literals`

Fixes the following exception under Python 3:
`TypeError: Object of type bytes is not JSON serializable`
KWierso/treeherder,KWierso/treeherder,edmorley/treeherder,KWierso/treeherder,edmorley/treeherder,edmorley/treeherder,edmorley/treeherder,KWierso/treeherder