[PATCH] initialize some variables in test to prevent -Wmaybe-uninitialized

Hello,

just noticed some warnings:
subversion/tests/libsvn_fs_base/fs-base-test.c:239:6: warning: 'present'
may be used uninitialized in this function [-Wmaybe-uninitialized] et
al. Initializing to boolean value that would fail the test if the
reference wasn't changed in called function at all.

[[[
* subversion/tests/libsvn_fs/fs-test.c
  (check_entry_present, check_entry_absent),
  subversion/tests/libsvn_fs_base/fs-base-test.c
  (check_entry_present, check_entry_absent, check_id_present,
  check_id_absent): initialize variable present to silence
  warning -Wmaybe-uninitialized
]]]

Andreas