remove exec_set_find_memory_regions

remove exec_set_find_memory_regions

exec_set_find_memory_regions is used to modify the exec target.
However, it only has a single caller, and so it is much clearer to
simply set the appropriate field directly.  It's also better for the
coming multi-target world to avoid this kind of global state change
anyway.

2014-02-19  Tom Tromey  <tromey@redhat.com>

	* gcore.h (objfile_find_memory_regions): Declare.
	* gcore.c (objfile_find_memory_regions): No longer static.  Add
	"self" argument.
	(_initialize_gcore): Don't call exec_set_find_memory_regions.
	* exec.c: Include gcore.h.
	(exec_set_find_memory_regions): Remove.
	(exec_find_memory_regions): Remove.
	(exec_do_find_memory_regions): Remove.
	(init_exec_ops): Update.
	* defs.h (exec_set_find_memory_regions): Remove.