Move Workstation Ostree installer to separate variant

Creating the image requires running lorax. There is however already one
lorax instance being run in the buildinstall phase. When the second one
runs, it overwrites the outputs from first one and people expecting to
boot netinst over PXE are instead getting ostree workstation.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1477916
Relates: https://pagure.io/pungi/issue/695
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

fedora.conf

@@ -800,7 +800,7 @@ ostree_installer = [
             'failable': ['*'],
         }
     }),
-    ("^Workstation$", {
+    ("^WorkstationOstree$", {
         "x86_64": {
             "repo": "Everything",
             "release": None,

variants-fedora.xml

@@ -133,6 +133,14 @@
             <package>fedora-productimg-workstation</package>
         </buildinstallpackages>
     </variant>
+    <variant id="WorkstationOstree" name="Workstation Ostree" type="variant" is_empty="true">
+        <arches>
+            <arch>aarch64</arch>
+            <arch>armhfp</arch>
+            <arch>i386</arch>
+            <arch>x86_64</arch>
+        </arches>
+    </variant>
     <variant name="Cloud" id="Cloud" type="variant">
         <arches>
             <arch>aarch64</arch>