Switching default of LH_APT from aptitude to apt for >= lenny.

Apt in lenny also supports tracking of 'orphaned' packages. If aptitude is
installed, apt can't be removed, so by switching to apt making the default
images a tiny bit smaller. And, aptitude got mainly default because of the
sarge->etch update recommendation.

functions/defaults.sh

@@ -34,7 +34,12 @@ Set_defaults ()
 	fi
 
 	# Setting package manager
-	LH_APT="${LH_APT:-aptitude}"
+	if [ "${LH_DISTRIBUTION}" = "etch" ]
+	then
+		LH_APT="${LH_APT:-aptitude}"
+	else
+		LH_APT="${LH_APT:-apt}"
+	fi
 
 	# Setting apt ftp proxy
 	if [ -z "${LH_APT_FTP_PROXY}" ] && [ -n "${ftp_proxy}" ]