Allow "capture info data" to not be a singleton.

Allow "capture info data" to not be a singleton.

It was buried as a static variable in capture_info.c, and functions were refactored to allow a pointer to the info_data_t structure to be passed in. TShark and GTK will have their own single (global) copy of the structure, while it opens up Qt to have multiple instances.

Change-Id: Ic2d7a2ad574de43f457cb18b194d6bc3fffb6120
Reviewed-on: https://code.wireshark.org/review/12691
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>