Quote applicationName in SyslogAppenderFactory

When using a user-defined String for the replacement of a regular
expression, we should be quoting it with `Matcher.quoteReplacement`, in
case they use any reserved characters (`/` or `$`).

In this case, we ran in to a problem with a Scala application with a
singleton object for the application, which gets compiled to a class
with a trailing `$`, causing a `StringIndexOutOfBoundsException` here.

dropwizard-logging/src/main/java/io/dropwizard/logging/SyslogAppenderFactory.java

@@ -189,7 +189,7 @@ public Appender<ILoggingEvent> build(LoggerContext context, String applicationNa
         final SyslogAppender appender = new SyslogAppender();
         appender.setName("syslog-appender");
         appender.setContext(context);
-        appender.setSuffixPattern(logFormat.replaceAll(LOG_TOKEN_PID, PID).replaceAll(LOG_TOKEN_NAME, applicationName));
+        appender.setSuffixPattern(logFormat.replaceAll(LOG_TOKEN_PID, PID).replaceAll(LOG_TOKEN_NAME, Matcher.quoteReplacement(applicationName)));
         appender.setSyslogHost(host);
         appender.setPort(port);
         appender.setFacility(facility.toString().toLowerCase(Locale.ENGLISH));