alias: don't shadow commands that we only partially matched (issue2993) (BC)

Previously, if you set an alias for "ci", it'd also shadow "commit"
even though you didn't specify that. This occurred for all commands
with explicit short variations.

mercurial/dispatch.py

@@ -366,7 +366,7 b' def addaliases(ui, cmdtable):'
             # definition might not exist or it might not be a cmdalias
             pass
 
-        cmdtable[aliasdef.cmd] = (aliasdef, aliasdef.opts, aliasdef.help)
+        cmdtable[aliasdef.name] = (aliasdef, aliasdef.opts, aliasdef.help)
         if aliasdef.norepo:
             commands.norepo += ' %s' % alias
 

tests/test-alias.t

@@ -4,6 +4,8 b''
   > graphlog=
   > 
   > [alias]
+  > # should clobber ci but not commit (issue2993)
+  > ci = version
   > myinit = init
   > cleanstatus = status -c
   > unknown = bargle
@@ -113,7 +115,7 b' no usage'
   no rollback information available
 
   $ echo foo > foo
-  $ hg ci -Amfoo
+  $ hg commit -Amfoo
   adding foo
 
 
@@ -195,7 +197,7 b' simple shell aliases'
   $ hg echo2 foo
   
   $ echo bar > bar
-  $ hg ci -qA -m bar
+  $ hg commit -qA -m bar
   $ hg count .
   1
   $ hg count 'branch(default)'