phabricator: use context manager form of progress in uploadchunks

Follow-up to 453079605242 / D7046.

Differential Revision: https://phab.mercurial-scm.org/D7134

hgext/phabricator.py

@@ -609,9 +609,9 b' def uploadchunks(fctx, fphid):'
     """
     ui = fctx.repo().ui
     chunks = callconduit(ui, b'file.querychunks', {b'filePHID': fphid})
-    progress = ui.makeprogress(
+    with ui.makeprogress(
         _(b'uploading file chunks'), unit=_(b'chunks'), total=len(chunks)
-    )
+    ) as progress:
     for chunk in chunks:
         progress.increment()
         if chunk[b'complete']:
@@ -628,7 +628,6 b' def uploadchunks(fctx, fphid):'
                 b'dataEncoding': b'base64',
             },
         )
-    progress.complete()
 
 
 def uploadfile(fctx):