SGF-515 - Allow a property to be unset.

src/test/java/org/springframework/data/gemfire/util/PropertiesBuilderTests.java

@@ -279,6 +279,16 @@ public class PropertiesBuilderTests {
 		assertThat(properties.getProperty("two"), is(equalTo("2")));
 	}
 
+	@Test
+	public void unsetPropertyIsSuccessful() {
+		Properties properties = PropertiesBuilder.create().unsetProperty("example").build();
+
+		assertThat(properties, is(notNullValue(Properties.class)));
+		assertThat(properties.size(), is(equalTo(1)));
+		assertThat(properties.containsKey("example"), is(true));
+		assertThat(properties.getProperty("example"), is(equalTo("")));
+	}
+
 	@Test
 	public void stringLiteralIsValuable() {
 		assertThat(PropertiesBuilder.create().isValuable("test"), is(true));