Use apps_shutdown() in all applications, in case someone decides not
to go the monolith way (does anyone do that these days?).

NOTE: a few applications are missing in this commit.  I've a few more
changes in them that I haven't tested yet.

apps/errstr.c

diff --git a/apps/errstr.c b/apps/errstr.c
index c411eff..fedb568 100644
--- a/apps/errstr.c
+++ b/apps/errstr.c
@@ -121,5 +121,6 @@
 			ret++;
 			}
 		}
+	apps_shutdown();
 	EXIT(ret);
 	}