gdb: add missing prepare_reinflate call in print_frame_info

gdb: add missing prepare_reinflate call in print_frame_info

print_frame_info calls frame_info_ptr::reinflate, but not
frame_info_ptr::prepare_reinflate, add the call to prepare_reinflate.
It works right now, because all callers of print_frame_info that could
possibly lead to the pretty printers being called, and the frame_info
objects being invalidated, do call prepare_reinflate themselves.  And
since the cached frame id is copied when passing a frame_info_ptr by
value, print_frame_info does have a cached frame id on entry.  So
technically, this change isn't needed.  But I don't think it's good for
a function to rely on its callers to have called prepare_reinflate, if
it intends to call reinflate.

Change-Id: Ie332b2d5479aef46f83fdc1120c7c83f4e84d1b0
Reviewed-By: Bruno Larsen <blarsen@redhat.com>