purge: avoid duplicate output for --print (issue4092)

Now "hg purge -p" commands avoids printiing duplication of filenames.

Second patch is the test coverage of first patch which tells that '-p'
does not depend on whether ui.verbose is configured or not,that means it
is independent of '-v'.

hgext/purge.py

@@ -101,10 +101,12 def purge(ui, repo, *dirs, **opts):
     status = repo.status(match=match, ignored=opts['all'], unknown=True)
 
     for f in sorted(status[4] + status[5]):
+        if act:
         ui.note(_('removing file %s\n') % f)
         remove(removefile, f)
 
     for f in sorted(directories, reverse=True):
         if match(f) and not os.listdir(repo.wjoin(f)):
+            if act:
             ui.note(_('removing directory %s\n') % f)
             remove(os.rmdir, f)

tests/test-purge.t

@@ -21,7 +21,7 setup
 delete an empty directory
 
   $ mkdir empty_dir
-  $ hg purge -p
+  $ hg purge -p -v
   empty_dir
   $ hg purge -v
   removing directory empty_dir