py3: force bytestr conversion of "reason" in scmutil.callcatch()

For instance, reason may be an InvalidURL as shown in added test.

mercurial/scmutil.py

@@ -262,7 +262,7 b' def callcatch(ui, func):'
             if isinstance(reason, pycompat.unicode):
                 # SSLError of Python 2.7.9 contains a unicode
                 reason = encoding.unitolocal(reason)
-            ui.error(_(b"abort: error: %s\n") % reason)
+            ui.error(_(b"abort: error: %s\n") % stringutil.forcebytestr(reason))
         elif (
             util.safehasattr(inst, b"args")
             and inst.args

tests/test-clone.t

@@ -614,6 +614,12 b' No local source'
   abort: repository a not found!
   [255]
 
+Invalid URL
+
+  $ hg clone http://invalid:url/a b
+  abort: error: nonnumeric port: 'url'
+  [255]
+
 No remote source
 
 #if windows