drum: update app index early when unlinking
The added logic also happens in +se-drop, which will get called by
+se-abet if we did unlink an application. But +se-agon depends on the
index being sane, and may be called between +se-klin and +se-abet.
::
++ se-klin :: disconnect app
|= gyl=gill:gall
- +>(eel (~(del in eel) gyl))
+ =/ gil=(unit gill:gall) se-agon
+ =. eel (~(del in eel) gyl)
+ ?~ gil +>.$
+ ?: =(gyl u.gil)
+ +>.$(inx 0)
+ (se-alas u.gil)
::
++ se-link :: connect to app
|= gyl=gill:gall
