iscsi: Fix iscsi_create

Since d5895fcb (iscsi: Split URL into individual options), creating
qcow2 image on an iscsi LUN fails:

    qemu-img create -f qcow2 iscsi://$SERVER/$IQN/0 1G
    qemu-img: iscsi://$SERVER/$IQN/0: Could not create image: Invalid
        argument

The problem is iscsi_open now expects that transport_name, portal and
target are already parsed into structured options by
iscsi_parse_filename, but it is not called in iscsi_create.
Signed-off-by: NFam Zheng <famz@redhat.com>
Message-id: 20170410075451.21329-1-famz@redhat.com
Reviewed-by: NEric Blake <eblake@redhat.com>
[mreitz: Dropped now superfluous
         qdict_put(bs_options, "filename", ...)]
Signed-off-by: NMax Reitz <mreitz@redhat.com>

block/iscsi.c

@@ -2092,6 +2092,7 @@ static int iscsi_create(const char *filename, QemuOpts *opts, Error **errp)
     BlockDriverState *bs;
     IscsiLun *iscsilun = NULL;
     QDict *bs_options;
+    Error *local_err = NULL;
 
     bs = bdrv_new();
 
@@ -2102,8 +2103,13 @@ static int iscsi_create(const char *filename, QemuOpts *opts, Error **errp)
     iscsilun = bs->opaque;
 
     bs_options = qdict_new();
-    qdict_put(bs_options, "filename", qstring_from_str(filename));
-    ret = iscsi_open(bs, bs_options, 0, NULL);
+    iscsi_parse_filename(filename, bs_options, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        ret = -EINVAL;
+    } else {
+        ret = iscsi_open(bs, bs_options, 0, NULL);
+    }
     QDECREF(bs_options);
 
     if (ret != 0) {