Create r1502267 backport branch.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1502267@1502268 13f79535-47bb-0310-9956-ffa450edef68
On the 1.8.x-r1502267 branch, backport r1502267 from trunk, with the
following changes:

* subversion/include/svn_version.h: Revert all r1502267 changes here.
  (svn_ver_check_list2): Revert addition of new API.
  (svn_ver_check_list): Revert deprecation.

* subversion/include/private/svn_subr_private.h
  (svn_ver_check_list2): Add it here instead, as a macro which aliases..
  (svn_ver__check_list2): .. this new function.

* subversion/libsvn_subr/version.c
  (svn_ver__check_list2): Implement svn_ver_check_list2() under this name.

* (everywhere): Add svn_subr_private.h includes to see svn_ver_check_list2().

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1502267@1502279 13f79535-47bb-0310-9956-ffa450edef68
Merge the 1.8.x-r1502267 branch:

 * r1502267
   Enforce strict version equality between cmdline tools and libraries.
   Justification:
     Without this, a 1.8.1 client will use a 1.8.2 libsvn_* library if that's
     what the runtime linker finds.  This may be a (hard-to-diagnose) problem
     due to possible incompatibilities in the subversion/include/private/ APIs
     used.
   Branch: 1.8.x-r1502267
   Notes:
     Seen in the wild under 1.7.x.
   Votes:
     +1: danielsh, stefan2, breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1516000 13f79535-47bb-0310-9956-ffa450edef68