Add --no-motd to and remove -l from rsync options. (#962)

This PR adds the --no-motd option to the default extra rsync options and
removes -l from the base rsync options.

This means we now have -rtO --delete as the base options and -z,
--contimeout=10, --max-size, and --no-motd as the default extra options that
can be overwritten.

doc/manual/source/manual-page.rst

@@ -1083,14 +1083,16 @@ All values can be overridden via the command line options.
             default is simply *rsync*.
 
       rsync-args
-            A list of strings containing the arguments to be passed to the
-            rsync command. Each string is an argument of its own.
-
-            If this option is not provided, Routinator will try to find out
-            if your rsync understands the ``--contimeout`` option and, if so,
-            will set it to 10 thus letting connection attempts time out after
-            ten seconds. If your rsync is too old to support this option, no
-            arguments are used.
+            A list of strings containing additional arguments to be passed
+            to the rsync command. Each string is an argument of its own.
+
+            The options ``-rtO --delete`` are always passed to the command.
+            The options listed in the option are added to it.
+
+            If the option is not provided, Routinator will add ``-z`` and
+            ``--no-motd``, as well as ``--contimeout=10`` if it is supported
+            by the rsync command, and ``--max-size`` if the
+            ``max-object-size`` option has not been set to 0.
 
       rsync-timeout
             An integer value specifying the number seconds an rsync command

src/collector/rsync.rs

@@ -469,6 +469,8 @@ impl RsyncCommand {
             Some(ref args) => args.clone(),
             None => {
                 let mut args = Vec::new();
+                args.push("--no-motd".into());
+                args.push("-z".into());
                 let has_contimeout =
                    output.stdout.windows(12)
                    .any(|window| window == b"--contimeout");
@@ -618,7 +620,7 @@ impl RsyncCommand {
         for item in &self.args {
             cmd.arg(item);
         }
-        cmd.arg("-rltz")
+        cmd.arg("-rtO")
            .arg("--delete")
            .arg(source.to_string())
            .arg(destination);