The text version
of LGPLv2.1 available at
http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt is slightly
different from COPYING.LIB:
- several paragraphs were rewrapped
- the FSF address has changed, so the license has been changed to
  indicate the newer address

I've checked that there are no changes in the license text apart from
the updated address, which is what I want to fix with this commit.