Another follow-up to r1149456: fix m4 escaping.
Another follow-up to r1149456: fix m4 escaping.

* build/ac-macros/berkeley-db.m4
  (SVN_LIB_BERKELEY_DB_TRY): Restore a lost set of []s.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion