at: BUILD fix

I don't care about the sedit vs. spelling out default_build,
but these things are/could become nasty..

utils/at/BUILD

@@ -1,10 +1,11 @@
-
 OPTS+=" --with-jobdir=/var/spool/atd \
-        --with-atspool=/var/spool/atd"
+        --with-atspool=/var/spool/atd" &&
 
 default_config &&
 make &&
 prepare_install &&
 make docdir=/usr/share/doc install &&
 
-[ -e /etc/at.deny ] || install -m644 at.deny /etc/
+if [ ! -e /etc/at.deny ]; then
+   install -m644 at.deny /etc/
+fi