Merge r1637826 from trunk:

 * r1637826
   Fix typos in LIBTOOL_M4 and LIBTOOL_CONFIG expansion in autogen.sh
   Justification:
     Makes no sense to tell users to set environment variables
     to fix builds with libtool in a nonstandard location, if we
     then don't interpret said environment variables correctly.
   Votes:
     +1: brane, stefan2, breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1643040 13f79535-47bb-0310-9956-ffa450edef68