Make rebuilddb work with the --root option. [#65993]

--- ./rpmdb/rpmdb.c.orig	2005-02-16 03:18:19.000000000 +0000
+++ ./rpmdb/rpmdb.c	2006-02-21 20:37:44.000000000 +0000
@@ -3771,7 +3887,7 @@ int rpmdbRebuild(const char * prefix, rp
     }
     dbpath = rootdbpath = rpmGetPath(prefix, tfn, NULL);
     if (!(prefix[0] == '/' && prefix[1] == '\0'))
-	dbpath += strlen(prefix);
+	dbpath += strlen(prefix) - 1;
     tfn = _free(tfn);
 
     /*@-nullpass@*/
@@ -3794,7 +3910,7 @@ int rpmdbRebuild(const char * prefix, rp
     }
     newdbpath = newrootdbpath = rpmGetPath(prefix, tfn, NULL);
     if (!(prefix[0] == '/' && prefix[1] == '\0'))
-	newdbpath += strlen(prefix);
+	newdbpath += strlen(prefix) - 1;
     tfn = _free(tfn);
 
     rpmMessage(RPMMESS_DEBUG, _("rebuilding database %s into %s\n"),