Disambiguate info_print_options

Disambiguate info_print_options

struct info_print_options is defined in both symtab.c and stack.c, which is
an ODR violation. So, I am renaming info_print_options and related
structs/functions in symtab.c:

info_print_options                ==> info_vars_funcs_options
info_print_options_defs           ==> info_vars_funcs_options_defs
make_info_print_options_def_group ==> make_info_vars_funcs_options_def_group
info_print_command_completer      ==> info_vars_funcs_command_completer

gdb/ChangeLog:

	* symtab.c (info_print_options): Rename to
	info_vars_funcs_options.
	(info_print_options_defs): Rename to
	info_vars_funcs_options_defs.
	(make_info_print_options_def_group): Rename to
	make_info_vars_funcs_options_def_group.
	(info_print_command_completer): Rename to
	info_vars_funcs_command_completer.
	(info_variables_command): Apply name changes.
	(info_functions_command): Likewise.
	(_initialize_symtab): Likewise.