Fixed issue with error

src/main/java/net/locusworks/logger/ApplicationLogger.java

@@ -471,7 +471,7 @@ public class ApplicationLogger implements org.slf4j.Logger {
   public void error(Map<String, String> values, String valueFormat, StringBuilder sb, Throwable e) {
     msgHelper(LogLevel.ERROR, values, valueFormat, sb);
     if (e != null) {
-      msgHelper("", e);
+      msgHelper(LogLevel.ERROR,"", e);
     }
   }