dispatch: tolerate non-standard version strings in tuplever() (issue3470)

When developing, we may see non-standard version strings of the form

  5d64306f39bb+20120525

which caused tuplever() to raise

  ValueError: invalid literal for int() with base 10: '5d64306f39bb'

and shadowing the real traceback.

mercurial/dispatch.py

@@ -252,8 +252,10 b' def _runcatch(req):'
     return -1
 
 def tuplever(v):
+    try:
     return tuple([int(i) for i in v.split('.')])
-
+    except ValueError:
+        return tuple()
 
 def aliasargs(fn, givenargs):
     args = getattr(fn, 'args', [])