Fix a test that doesn't execute in its sandbox.

Patch by: Lieven Govaerts <lgo@mobsol.be>

* subversion/tests/cmdline/schedule_tests.py:
  (delete_non_existent): cd to the sandbox wc before running the test.

Index: subversion/tests/cmdline/schedule_tests.py
===================================================================
--- subversion/tests/cmdline/schedule_tests.py  (revision 19012)
+++ subversion/tests/cmdline/schedule_tests.py  (working copy)
@@ -669,10 +669,16 @@

   sbox.build()
   wc_dir = sbox.wc_dir
-  svntest.actions.run_and_verify_svn(None, None, SVNAnyOutput,
-                                     'rm', '--force', 'non-existent')
+
+  was_cwd = os.getcwd()
+  os.chdir(wc_dir)
+
+  try:
+    svntest.actions.run_and_verify_svn(None, None, SVNAnyOutput,
+                                       'rm', '--force', 'non-existent')
+  finally:
+    os.chdir(was_cwd)

-
 ########################################################################
 # Run the tests