fix SpecFilter dropping HEAD ops

Author: q3aiml

modules/swagger-core/src/main/java/io/swagger/core/filter/SpecFilter.java

@@ -48,6 +48,7 @@ public Swagger filter(Swagger swagger, SwaggerSpecFilter filter, Map<String, Lis
             Path path = swagger.getPaths().get(resourcePath);
             Map<String, Operation> ops = new HashMap<String, Operation>();
             ops.put("get", path.getGet());
+            ops.put("head", path.getHead());
             ops.put("put", path.getPut());
             ops.put("post", path.getPost());
             ops.put("delete", path.getDelete());

modules/swagger-core/src/test/resources/specFiles/petstore.json

@@ -356,6 +356,28 @@
             "description": "Invalid ID supplied"
           }
         }
+      },
+      "head": {
+        "tags": [
+          "pet"
+        ],
+        "parameters": [
+          {
+            "name": "petId",
+            "in": "path",
+            "description": "ID of pet that needs to be fetched",
+            "required": true,
+            "type": "string"
+          }
+        ],
+        "responses": {
+          "404": {
+            "description": "Pet not found"
+          },
+          "400": {
+            "description": "Invalid ID supplied"
+          }
+        }
       }
     },
     "/user/logout": {