more plural -> singular cleanups

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

conf/explorer/pkg_system

@@ -19,7 +19,7 @@
 #
 #
 
-os="$("$__explorers/os")"
+os="$("$__explorer/os")"
 
 case "$os" in
       archlinux) echo pacman ;;

conf/manifest/init

@@ -4,7 +4,7 @@
 
 # This is debug and should not be in a production environment
 echo "Running initial manifest for $__target_host"
-echo "We could access other manifests in $__manifests"
+echo "We could access other manifests in $__manifest"
 
 case "$__target_host" in
    localhost)