cleanup: remove some unused / duplicate imports

hgext/convert/cvsps.py

@@ -8,7 +8,6 b''
 import os
 import re
 import cPickle as pickle
-from mercurial import util
 from mercurial.i18n import _
 from mercurial import hook
 from mercurial import util

hgext/extdiff.py

@@ -63,7 +63,7 b' pretty fast (at least faster than having'
 
 from mercurial.i18n import _
 from mercurial.node import short, nullid
-from mercurial import cmdutil, scmutil, scmutil, util, commands, encoding
+from mercurial import cmdutil, scmutil, util, commands, encoding
 import os, shlex, shutil, tempfile, re
 
 cmdtable = {}

hgext/shelve.py

@@ -25,7 +25,7 b' from mercurial.i18n import _'
 from mercurial.node import nullid, nullrev, bin, hex
 from mercurial import changegroup, cmdutil, scmutil, phases, commands
 from mercurial import error, hg, mdiff, merge, patch, repair, util
-from mercurial import templatefilters, changegroup, exchange
+from mercurial import templatefilters, exchange
 from mercurial import lock as lockmod
 from hgext import rebase
 import errno