Allow properties with a default value to be overridden by an environment variable, to be consistent with the handling of properties without a default value

src/main/java/ca/uhn/fhir/jpa/starter/HapiProperties.java

@@ -178,15 +178,11 @@ public class HapiProperties {
     }
 
     private static String getProperty(String propertyName, String defaultValue) {
-        Properties properties = HapiProperties.getProperties();
+        String value = getProperty(propertyName);
-
-        if (properties != null) {
-            String value = properties.getProperty(propertyName);
 
         if (value != null && value.length() > 0) {
             return value;
         }
-        }
 
         return defaultValue;
     }