[binutils-gdb] dwarf2read: Replace copy_string usages with savestring

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 3f8a7804287d3153fb4a8676b7304e67cca32be4 ***

Author: Simon Marchi <simon.marchi@ericsson.com>
Branch: master
Commit: 3f8a7804287d3153fb4a8676b7304e67cca32be4

dwarf2read: Replace copy_string usages with savestring

copy_string does the exact same thing as savestring, so replace the
usages of the former with the latter.

gdb/ChangeLog:

	* dwarf2read.c (copy_string): Remove.
	(parse_macro_definition): Replace copy_string with savestring.