Add and use exception constructor that takes httpCode

src/main/java/com/hellosign/sdk/HelloSignException.java

@@ -50,6 +50,10 @@ public HelloSignException(String message, Throwable e) {
         super(message, e);
     }
 
+    public HelloSignException(String message, Integer httpCode) {
+        this(message, httpCode, null, null);
+    }
+
     public HelloSignException(String message, Integer httpCode, String type) {
         this(message, httpCode, type, null);
     }

src/main/java/com/hellosign/sdk/http/HttpClient.java

@@ -279,7 +279,7 @@ public int asHttpCode() throws HelloSignException {
             reset();
             return code;
         }
-        throw new HelloSignException("HTTP Code " + code);
+        throw new HelloSignException("HTTP Code " + code, code);
     }
 
     /**

src/test/java/com/hellosign/sdk/HelloSignClientTest.java

@@ -597,10 +597,16 @@ public void testCancelSignatureRequest() throws Exception {
         assertTrue(client.cancelSignatureRequest("9cc3d5819959419abee4dbff2073d497e7c0a962"));
     }
 
-    @Test(expected = HelloSignException.class)
+    @Test
     public void testCancelSignatureRequestInvalid() throws Exception {
         mockResponseCode(410);
-        client.cancelSignatureRequest("foo");
+        try {
+            client.cancelSignatureRequest("foo");
+            fail("Expected HelloSignException");
+        } catch (HelloSignException e) {
+            assertEquals("HTTP Code 410", e.getMessage());
+            assertEquals(410, (int) e.getHttpCode());
+        }
     }
 
     @Test