Fix leak of strings in openfontdlg.c FVOpenFont()

A list of glyph list names was created for display in the "Open Font"
dialog.  The name strings were stuffed into the dialog creation data
structures.  After the dialog was dismissed, nobody was `free()`ing those
name strings.

Moved the names list array `free()` to end of dialog routine, and first
used that list to locate and `free()` all the name strings.

Tested and previous leaks now gone from `valgrind` reports.