Change legacy "persona" references to userid_t.

Offers stronger typing with no functional change.

Change-Id: I09f0262470feec5cfdf26658f998c20550af84d4
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index 87f900a..1904408 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -83,7 +83,7 @@
     int64_t asecsize = 0;
     int res = 0;
 
-        /* pkgdir, persona, apkpath */
+        /* pkgdir, userid, apkpath */
     res = get_size(arg[0], atoi(arg[1]), arg[2], arg[3], arg[4], arg[5],
             &codesize, &datasize, &cachesize, &asecsize);
 
@@ -108,7 +108,7 @@
 
 static int do_rm_user(char **arg, char reply[REPLY_MAX])
 {
-    return delete_persona(atoi(arg[0])); /* userid */
+    return delete_user(atoi(arg[0])); /* userid */
 }
 
 static int do_movefiles(char **arg, char reply[REPLY_MAX])