Remove glusterfs-nfs job

It always fails and is unmaintained.

Change-Id: I76e279bf8aeccea1fece8bbd78b899a6a5663bed
diff --git a/.zuul.yaml b/.zuul.yaml
index aea5104..1e44daf 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -20,8 +20,6 @@
             voting: false
         - manila-tempest-minimal-dsvm-cephfs-nfs-centos-7:
             voting: false
-        - manila-tempest-dsvm-glusterfs-nfs:
-            voting: false
         - manila-tempest-minimal-dsvm-dummy
         - manila-tempest-minimal-dsvm-lvm-centos-7
     gate: