[FAB-3722] /examples/cluster: Use /var

We were allowing the CA to write persistent files to our
/etc volume mount.  This is both poor-form as well as
problematic since it may cause root-owned files to
cause problems with removing the container.

Fixes FAB-3722

Change-Id: Ibda7c0e09c34517711d5870f42f9aebfffdd0549
Signed-off-by: Greg Haskins <gregory.haskins@gmail.com>

examples/cluster/config/fabric-ca-server-config.yaml

@@ -122,7 +122,7 @@ registry:
 #############################################################################
 db:
   type: sqlite3
-  datasource: /var/hyperledger/fabric-ca-server.db
+  datasource: /var/hyperledger/fabric-ca-server/state.db
   tls:
       enabled: false
       certfiles:
@@ -206,7 +206,7 @@ bccsp:
         security: 256
         filekeystore:
             # The directory used for the software file-based keystore
-            keystore: keystore
+            keystore: /var/hyperledger/fabric-ca-server/keystore
 
 #############################################################################
 # The fabric-ca-server init and start commands support the following two