Change the type of copy_names from int to bool

Change the type of copy_names from int to bool

This parameter is really a boolean, so change the type accordingly
and update the callers.

This is for symbol_set_names, add_psymbol_to_bcache, and
add_psymbol_to_list.

minimal_symbol_reader::record_full was already passing a bool
to symbol_set_names.

gdb/ChangeLog:

2019-09-11  Christian Biesinger  <cbiesinger@google.com>

	* dbxread.c (read_dbx_symtab): Update.
	* dwarf2read.c (load_partial_dies): Update.
	* mdebugread.c (parse_partial_symbols): Update.
	(handle_psymbol_enumerators): Update.
	* psympriv.h (add_psymbol_to_list): Change type of copy_names to bool.
	* psymtab.c (add_psymbol_to_bcache): Likewise.
	(add_psymbol_to_list): Likewise.
	* symtab.c (symbol_set_names): Likewise.
	* symtab.h (symbol_set_names): Likewise.
	* xcoffread.c (scan_xcoff_symtab): Update.