spec: rebase field numbers for v1

The spec package name was recently changed to v1, providing us the
chance to properly number message fields starting from 1.

* ControllerGetCapabilitiesResponse
* GetPluginCapabilitiesResponse

Author: James DeFelice

csi.proto

@@ -107,7 +107,7 @@ message GetPluginCapabilitiesRequest {
 message GetPluginCapabilitiesResponse {
   // All the capabilities that the controller service supports. This
   // field is OPTIONAL.
-  repeated PluginCapability capabilities = 2;
+  repeated PluginCapability capabilities = 1;
 }
 
 // Specifies a capability of the plugin.
@@ -798,7 +798,7 @@ message ControllerGetCapabilitiesRequest {
 message ControllerGetCapabilitiesResponse {
   // All the capabilities that the controller service supports. This
   // field is OPTIONAL.
-  repeated ControllerServiceCapability capabilities = 2;
+  repeated ControllerServiceCapability capabilities = 1;
 }
 
 // Specifies a capability of the controller service.