Follow up to r987956 by removing useless part of autoconf macro.  (m4 sux.)
Follow up to r987956 by removing useless part of autoconf macro.  (m4 sux.)

* build/ac-macros/serf.m4
  (SVN_LIB_SERF): Make #error consistent with AC_MSG_WARN notice.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@988814 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion