Remove mount cache for cephfs

PR #282 introduces the mount cache to
solve cephfs fuse mount issue when cephfs plugin pod
restarts .This is not working as intended. This PR removes
the code for maintainability.
Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

deploy/cephfs/kubernetes/csi-cephfsplugin.yaml

@@ -63,7 +63,6 @@ spec:
             - "--v=5"
             - "--drivername=cephfs.csi.ceph.com"
             - "--metadatastorage=k8s_configmap"
-            - "--mountcachedir=/mount-cache-dir"
             - "--metricsport=8090"
             - "--metricspath=/metrics"
             - "--enablegrpcmetrics=false"
@@ -84,8 +83,6 @@ spec:
               value: unix:///csi/csi.sock
           imagePullPolicy: "IfNotPresent"
           volumeMounts:
-            - name: mount-cache-dir
-              mountPath: /mount-cache-dir
             - name: socket-dir
               mountPath: /csi
             - name: mountpoint-dir
@@ -130,8 +127,6 @@ spec:
               mountPath: /csi
           imagePullPolicy: "IfNotPresent"
       volumes:
-        - name: mount-cache-dir
-          emptyDir: {}
         - name: socket-dir
           hostPath:
             path: /var/lib/kubelet/plugins/cephfs.csi.ceph.com/