Fix some dates in the changelog; add some recent changes to the changelog.

Apparently rpmbuild now verifies the dates (including the day of the week)
you entered.

Change-Id: I1c67fb3170de3199b5fe5f8c117eaefb4d4d28c7
Reviewed-on: https://code.wireshark.org/review/3442
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>