lnrpc: remove confirmation_height from PendingOpenChannel proto

lnrpc/lightning.proto

@@ -2369,9 +2369,6 @@ message PendingChannelsResponse {
         // The pending channel
         PendingChannel channel = 1;
 
-        // The height at which this channel will be confirmed
-        uint32 confirmation_height = 2;
-
         /*
         The amount calculated to be paid in fees for the current set of
         commitment transactions. The fee amount is persisted with the channel
@@ -2390,6 +2387,9 @@ message PendingChannelsResponse {
         transaction. This value can later be updated once the channel is open.
         */
         int64 fee_per_kw = 6;
+
+        // Previously used for confirmation_height. Do not reuse.
+        reserved 2;
     }
 
     message WaitingCloseChannel {

lnrpc/lightning.swagger.json

@@ -2792,11 +2792,6 @@
           "$ref": "#/definitions/PendingChannelsResponsePendingChannel",
           "title": "The pending channel"
         },
-        "confirmation_height": {
-          "type": "integer",
-          "format": "int64",
-          "title": "The height at which this channel will be confirmed"
-        },
         "commit_fee": {
           "type": "string",
           "format": "int64",