Re-do new 'desktop_clean' needles

The F26 background does not change with the time of day, so that
needle should serve as-is, it's just no use for Rawhide. For
Rawhide, let's try a needle with an OCR match on 'Activities',
plus a tiny match area for a pure white block (expected to be
matched in the user menu area), since os-autoinst requires all
needles to include a match area for some reason.

needles/gnome/desktop_clean-20170616-f26.json

@@ -0,0 +1,25 @@
+{
+  "properties": [],
+  "area": [
+    {
+      "type": "match",
+      "width": 67,
+      "xpos": 9,
+      "height": 15,
+      "ypos": 7
+    },
+    {
+      "type": "match",
+      "xpos": 970,
+      "width": 43,
+      "height": 18,
+      "ypos": 4
+    }
+  ],
+  "tags": [
+    "DESKTOP-gnome",
+    "ENV-DISTRI-fedora",
+    "LANGUAGE-english",
+    "graphical_desktop_clean"
+  ]
+}

needles/gnome/desktop_clean-20170616-rawhide_ocr.json

@@ -0,0 +1,25 @@
+{
+    "area": [
+        {
+            "height": 15,
+            "type": "ocr",
+            "width": 67,
+            "xpos": 9,
+            "ypos": 6
+        },
+        {
+            "height": 1,
+            "type": "match",
+            "width": 1,
+            "xpos": 946,
+            "ypos": 12
+        }
+    ],
+    "properties": [],
+    "tags": [
+        "DESKTOP-gnome",
+        "ENV-DISTRI-fedora",
+        "LANGUAGE-english",
+        "graphical_desktop_clean"
+    ]
+}