added check, warning for missing http method swagger-api/swagger-codegen#612

Author: fehguy

modules/swagger-compat-spec-parser/src/main/java/io/swagger/parser/SwaggerCompatConverter.java

@@ -478,7 +478,12 @@ else if(resourceListing.getApiVersion() != null) {
         }
         for(io.swagger.models.apideclaration.Operation op : ops) {
           Operation operation = convertOperation(tag, op);
-          path.set(op.getMethod().toString().toLowerCase(), operation);
+          if(op.getMethod() != null) {
+            path.set(op.getMethod().toString().toLowerCase(), operation);
+          }
+          else {
+            System.out.println("skipping operation with missing method:\n" + Json.pretty(operation));
+          }
         }
       }