qapi: qapi-commands.py option --type is unused, drop it

Anything but --type sync (which is the default) suppresses output
entirely, which makes no sense.

Dates back to the initial commit c17d990.  Commit message says
"Currently only generators for synchronous qapi/qmp functions are
supported", so maybe output other than "synchronous qapi/qmp" was
planned at the time, to be selected with --type.

Should other kinds of output ever materialize, we can put the option
back.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

scripts/qapi-commands.py

@@ -381,14 +381,13 @@ try:
     opts, args = getopt.gnu_getopt(sys.argv[1:], "chp:i:o:m",
                                    ["source", "header", "prefix=",
                                     "input-file=", "output-dir=",
-                                    "type=", "middle"])
+                                    "middle"])
 except getopt.GetoptError, err:
     print str(err)
     sys.exit(1)
 
 output_dir = ""
 prefix = ""
-dispatch_type = "sync"
 c_file = 'qmp-marshal.c'
 h_file = 'qmp-commands.h'
 middle_mode = False
@@ -403,8 +402,6 @@ for o, a in opts:
         input_file = a
     elif o in ("-o", "--output-dir"):
         output_dir = a + "/"
-    elif o in ("-t", "--type"):
-        dispatch_type = a
     elif o in ("-m", "--middle"):
         middle_mode = True
     elif o in ("-c", "--source"):
@@ -436,7 +433,6 @@ exprs = parse_schema(input_file)
 commands = filter(lambda expr: expr.has_key('command'), exprs)
 commands = filter(lambda expr: not expr.has_key('gen'), commands)
 
-if dispatch_type == "sync":
 fdecl = maybe_open(do_h, h_file, 'w')
 fdef = maybe_open(do_c, c_file, 'w')
 ret = gen_command_decl_prologue(header=basename(h_file), guard=guardname(h_file), prefix=prefix)