Fix #23 Priority calculation for rfc3164

Author: Spyros Pachomis

src/main/java/com/cloudbees/syslog/SyslogMessage.java

@@ -341,7 +341,7 @@ public String toRfc3164SyslogMessage() {
      */
     public void toRfc3164SyslogMessage(Writer out) throws IOException {
 
-        int pri = facility.numericalCode() + severity.numericalCode();
+        int pri = facility.numericalCode() * 8 + severity.numericalCode();
 
         out.write('<');
         out.write(Integer.toString(pri));

src/test/java/com/cloudbees/syslog/SyslogMessageTest.java

@@ -111,7 +111,7 @@ public void testRfc3164Format() throws Exception {
                 .withMsg("a syslog message");
 
         String actual = message.toRfc3164SyslogMessage();
-        String expected = "<7>Dec 05 10:30:05 myserver.example.com my_app: a syslog message";
+        String expected = "<14>Dec 05 10:30:05 myserver.example.com my_app: a syslog message";
 
         assertThat(actual, is(expected));