gtk: fix memory leak in profile dialog.

gtk: fix memory leak in profile dialog.

fill_list() don't break the loop when it founds first profile matching
name, and it can memleak if somehow it found more than one.
Don't break the loop to avoid regressions. Just g_free() previously found.
Found by clang.

Change-Id: I082b3f1d16f07580a6d7c814d2a8ee5463a44b0f
Reviewed-on: https://code.wireshark.org/review/25422
Petri-Dish: Jakub Zawadzki <darkjames-ws@darkjames.pl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Jakub Zawadzki <darkjames-ws@darkjames.pl>