Followup to r1507889:

* Makefile.in
  (APXS): Strip whitespace at the end of the definition, which propagates to
    the value.

* subversion/tests/cmdline/davautocheck.sh
  (APXS): Fix the sniffing from Makefile so that it works not only when
    grep/sed failed, but also when they succeeded (by promoting the setting
    of the parameter outside of a subshell).

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1507891 13f79535-47bb-0310-9956-ffa450edef68