ChangeLog.rst: fix issues from #294 merge
ChangeLog.rst: fix issues from #294 merge

The new changelog entries should go in the 1.0 dev section, not 0.12.
Also removed a near-duplicate entry that was erroneously merged into
PR #294.

hemberger/MechanicalSoup,MechanicalSoup/MechanicalSoup,hickford/MechanicalSoup