Unpause fedora-34 and opensuse-15 image builds

Fedora-34 was paused until bug fixes could land in DIB and our nodepool
builder images could be updated. This happened about 2 weeks ago from
what I can tell so unpause and let those images build again.

Opensuse-15 was paused becuase the images failed to build. Unfortunately
that was almost a year ago and we don't have logs for why this was
broken. Unpause to generate new logs allowing us to debug them.

Change-Id: I7d1957304d90b9902f36eab8f45871e081373282

nodepool/nodepool.yaml

@@ -214,7 +214,7 @@ diskimages:
 
   - name: fedora-34
     parent: base
-    pause: true
+    pause: false
     python-path: /usr/bin/python3
     elements:
       - fedora-container
@@ -317,8 +317,9 @@ diskimages:
   - name: opensuse-15
     parent: base
     # NOTE(ianw): Paused 2020-12-18 due to persistent build failures
-    # pending investigation
-    pause: true
+    # pending investigation. Unpausing as images were deleted and we need
+    # new builds to debug.
+    pause: false
     elements:
       - opensuse-minimal
       - cache-devstack