__single_binary_service: fix oddities when removing a service

We were requiring too many arguments

type/__single_binary_service/man.rst

@@ -27,15 +27,6 @@ This type supports services managed by `__runit(7)` when `systemd` is not
 the init system being used.
 
 
-REQUIRED PARAMETERS
--------------------
-version
-    This type will use a thumbstone file with a "version" number to track
-    whether or not a service must be updated.
-    This thumbstone file is placed under
-    `/usr/local/bin/.${__object_id}.cdist.version`.
-
-
 BOOLEAN PARAMETERS
 ------------------
 unpack
@@ -52,6 +43,13 @@ do-not-manage-user
 
 OPTIONAL PARAMETERS
 -------------------
+version
+    Required when installing a service.
+    This type will use a thumbstone file with a "version" number to track
+    whether or not a service must be updated.
+    This thumbstone file is placed under
+    `/usr/local/bin/.${__object_id}.cdist.version`.
+
 checksum
     This will be passed verbatim to `__download(7)`.
     Use something like `sha256:...`.

type/__single_binary_service/manifest

@@ -87,10 +87,16 @@ fi
 SERVICE_DEFINITION="$(cat "${__object}/parameter/service-definition" 2>/dev/null || true)"
 
 CHECKSUM="$(cat "${__object}/parameter/checksum")"
-SHOULD_VERSION="$(cat "${__object}/parameter/version")"
+SHOULD_VERSION="$(cat "${__object}/parameter/version" 2>/dev/null || true)"
 DOWNLOAD_URL="$(cat "${__object}/parameter/url")"
 LOCAL_SOURCE="$(cat "${__object}/parameter/local-source")"
-if [ -z "${DOWNLOAD_URL}${LOCAL_SOURCE}" ]; then
+if [ "${STATE}" = "present" ] && [ -z "${SHOULD_VERSION}" ]; then
+	cat >&1 <<-EOM
+	When installing a service, --version must be specified.
+	EOM
+	exit 1
+fi
+if [ "${STATE}" = "present" ] && [ -z "${DOWNLOAD_URL}${LOCAL_SOURCE}" ]; then
 	cat >&1 <<-EOM
 	Exactly one of --url or --local-source must be specified.
 	EOM

type/__single_binary_service/parameter/optional

@@ -15,5 +15,6 @@ unpack-extension
 unpack-args
 url
 user-home-dir
+version
 working-directory
 working-directory-permissions

type/__single_binary_service/parameter/required

@@ -1 +0,0 @@
-version