Always put editor-modelines at the end of the file ...

... to ensure that there are no potential issues with respect to
editors limiting the number of lines scanned at the end of the file
when checking for editor modelines.

Change-Id: Ic85cbb108bb5159d6ec4116fea11f5eebb4e44a4
Reviewed-on: https://code.wireshark.org/review/4688
Reviewed-by: Bill Meier <wmeier@newsguy.com>