histedit: fix style of new error message

histedit: fix style of new error message

- lowercase
- no punctuation
- brief
- short node

--- a/hgext/histedit.py	Wed Feb 04 15:17:13 2015 -0500
+++ b/hgext/histedit.py	Tue Mar 03 17:28:05 2015 -0600
@@ -1026,9 +1026,8 @@
         strip_nodes = set([repo[n].hex() for n in nodelist])
         common_nodes = histedit_nodes & strip_nodes
         if common_nodes:
-            raise util.Abort(_('unable to strip %s. Nodes are '
-                               'used by history edit in progress.')
-                             % ', '.join(common_nodes))
+            raise util.Abort(_("histedit in progress, can't strip %s")
+                             % ', '.join(node.short(x) for x in common_nodes))
     return orig(ui, repo, nodelist, *args, **kwargs)
 
 extensions.wrapfunction(repair, 'strip', stripwrapper)

--- a/tests/test-histedit-edit.t	Wed Feb 04 15:17:13 2015 -0500
+++ b/tests/test-histedit-edit.t	Tue Mar 03 17:28:05 2015 -0600
@@ -88,7 +88,7 @@
 
 Try to delete necessary commit
   $ hg strip -r 652413bf663e
-  abort: unable to strip 652413bf663ef2a641cab26574e46d5f5a64a55a. Nodes are used by history edit in progress.
+  abort: histedit in progress, can't strip 363532343133
   [255]
 
 commit, then edit the revision