Remove some dead code.

Due to the prior condition only the else blocks of these statements
will be run.

* subversion/libsvn_subr/mergeinfo.c
  (svn_mergeinfo__adjust_mergeinfo_rangelists): Remove if/else blocks
    where only the else statement will ever run.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1469562 13f79535-47bb-0310-9956-ffa450edef68