Improve handling of temporary allocations in the mergeinfo parsing code.
Improve handling of temporary allocations in the mergeinfo parsing code.

* subversion/libsvn_subr/mergeinfo.c
  (parse_revision_line): Rename the POOL parameter to SCRATCH_POOL.
   Use the scratch pool for temporary allocations. Store results in the
   pool which the provided mergeinfo hash was allocated in.
  (parse_top): Use an iterpool while calling parse_revision_line() in a loop.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion