py3: make contrib/dumprevlog use print_function

contrib/dumprevlog

@@ -1,31 +1,31 b''
 #!/usr/bin/env python
 # Dump revlogs as raw data stream
 # $ find .hg/store/ -name "*.i" | xargs dumprevlog > repo.dump
 
-from __future__ import absolute_import
+from __future__ import absolute_import, print_function
 
 import sys
 from mercurial import (
     node,
     revlog,
     util,
 )
 
 for fp in (sys.stdin, sys.stdout, sys.stderr):
     util.setbinary(fp)
 
 for f in sys.argv[1:]:
     binopen = lambda fn: open(fn, 'rb')
     r = revlog.revlog(binopen, f)
-    print "file:", f
+    print("file:", f)
     for i in r:
         n = r.node(i)
         p = r.parents(n)
         d = r.revision(n)
-        print "node:", node.hex(n)
-        print "linkrev:", r.linkrev(i)
-        print "parents:", node.hex(p[0]), node.hex(p[1])
-        print "length:", len(d)
-        print "-start-"
-        print d
-        print "-end-"
+        print("node:", node.hex(n))
+        print("linkrev:", r.linkrev(i))
+        print("parents:", node.hex(p[0]), node.hex(p[1]))
+        print("length:", len(d))
+        print("-start-")
+        print(d)
+        print("-end-")