add_cdrom: Update docs for adding ISO images.

See also RHBZ#563450 (NB: This commit does not fix the bug).

diff --git a/src/generator.ml b/src/generator.ml
index 44dc8a5..2cede47 100755 (executable)
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -505,10 +505,24 @@ This function adds a virtual CD-ROM disk image to the guest.
 
 This is equivalent to the qemu parameter C<-cdrom filename>.
 
-Note that this call checks for the existence of C<filename>.  This
+Notes:
+
+=over 4
+
+=item *
+
+This call checks for the existence of C<filename>.  This
 stops you from specifying other types of drive which are supported
 by qemu such as C<nbd:> and C<http:> URLs.  To specify those, use
-the general C<guestfs_config> call instead.");
+the general C<guestfs_config> call instead.
+
+=item *
+
+If you just want to add an ISO file (often you use this as an
+efficient way to transfer large files into the guest), then you
+should probably use C<guestfs_add_drive_ro> instead.
+
+=back");
 
   ("add_drive_ro", (RErr, [String "filename"]), -1, [FishAlias "add-ro"],
    [],