util: move md5 back next to sha1 and allow to call it without an argument

This effectively backs out changeset 908c5906091b.

The API change is done so that both util.sha1 and util.md5 can be called the
same way. The function is moved in order to use it for md5 checksumming for
an upcoming bundle2 feature.

mercurial/keepalive.py

@@ -19,8 +19,6 b''
 #  - fix for digest auth (inspired from urllib2.py @ Python v2.4)
 # Modified by Dirkjan Ochtman:
 #  - import md5 function from a local util module
-# Modified by Martin Geisler:
-#  - moved md5 function from local util module to this module
 # Modified by Augie Fackler:
 #  - add safesend method and use it to prevent broken pipe errors
 #    on large POST requests
@@ -617,16 +615,8 b' def error_handler(url):'
     print "open connections:", hosts
     keepalive_handler.close_all()
 
-def md5(s):
-    try:
-        from hashlib import md5 as _md5
-    except ImportError:
-        from md5 import md5 as _md5
-    global md5
-    md5 = _md5
-    return _md5(s)
-
 def continuity(url):
+    from util import md5
     format = '%25s: %s'
 
     # first fetch the file with the normal http handler

mercurial/util.py

@@ -108,6 +108,15 b" def _fastsha1(s=''):"
     _fastsha1 = sha1 = _sha1
     return _sha1(s)
 
+def md5(s=''):
+    try:
+        from hashlib import md5 as _md5
+    except ImportError:
+        from md5 import md5 as _md5
+    global md5
+    md5 = _md5
+    return _md5(s)
+
 try:
     buffer = buffer
 except NameError: