httppeer: properly gate debug usage behind debug flag check

The "dbg" local variable is only defined if the 'debugflag' is set to True.
However, it was used indiscriminately later in the function. We hide its usage
behind the 'debugflag' value to avoid raising a NameError.

mercurial/httppeer.py

@@ -319,7 +319,7 b' def sendrequest(ui, opener, req):'
         ui.traceback()
         raise IOError(None, inst)
     finally:
-        if ui.configbool('devel', 'debug.peer-request'):
+        if ui.debugflag and ui.configbool('devel', 'debug.peer-request'):
             dbg(line % '  finished in %.4f seconds (%d)'
                 % (util.timer() - start, res.code))