Update all sourceware links to https.  The website redirects
everything to https anyway so let the web server do a bit less work.
The only reference that remains unchanged is the one in the old
ChangeLog, since it didn't seem worth changing it.

	* NEWS: Update sourceware link to https.
	* configure.ac: Likewise.
	* crypt/md5test-giant.c: Likewise.
	* dlfcn/bug-atexit1.c: Likewise.
	* dlfcn/bug-atexit2.c: Likewise.
	* localedata/README: Likewise.
	* malloc/tst-mallocfork.c: Likewise.
	* manual/install.texi: Likewise.
	* nptl/tst-pthread-getattr.c: Likewise.
	* stdio-common/tst-fgets.c: Likewise.
	* stdio-common/tst-fwrite.c: Likewise.
	* sunrpc/Makefile: Likewise.
	* sysdeps/arm/armv7/multiarch/memcpy_impl.S: Likewise.
	* wcsmbs/tst-mbrtowc2.c: Likewise.
	* configure: Regenerate.
	* INSTALL: Regenerate.