Revert "Replace submission plugin section header with label"

This reverts commit 7e41db8dda800c975445b2c9d827be823d41358d.
Fixing warnings when user has no views

See https://github.com/catalyst/moodle-assignsubmission-mahara/issues/12

I missed a few parts the first time I tried to cherry-pick this...

Conflicts:

	locallib.php
In Moodle 2.7 headers are no longer automatically generated