fix(apm): rebuild lost cursor info on pre-OP_QUERY responses

Author: mbroadst

lib/apm.js

@@ -518,7 +518,9 @@ var Instrumentation = function(core, options, callback) {
             } else {
               if (r && r.documents) {
                 r = r.documents[0];
-              } else if (commandName.toLowerCase() === 'getmore' && r == null) {
+              }
+
+              if (commandName.toLowerCase() === 'getmore' && r.cursor == null) {
                 r = {
                   cursor: {
                     id: cursor.cursorState.cursorId,
@@ -531,7 +533,7 @@ var Instrumentation = function(core, options, callback) {
                 (commandName.toLowerCase() === 'find' ||
                   commandName.toLowerCase() === 'aggregate' ||
                   commandName.toLowerCase() === 'listcollections') &&
-                r == null
+                r.cursor == null
               ) {
                 r = {
                   cursor: {