Update args4j to snapshot built from current CVS

We need this snapshot of the args4j code to pick up a change where
the CmdLineParser class exposed its addOption and addArgument
methods by making them public.  Ulrik's change Ia23461f8b65c5f94
requires these to implement the command line gerrit approve tool.

Change-Id: I61850e68176bb8fcbde8f02ebed9f35ebd988cc0
Signed-off-by: Shawn O. Pearce <sop@google.com>
CC: Ulrik Sjölin <ulrik.sjolin@gmail.com>

pom.xml

diff --git a/pom.xml b/pom.xml
index 1051d22..335b4fd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -546,7 +546,7 @@
     <dependency>
       <groupId>args4j</groupId>
       <artifactId>args4j</artifactId>
-      <version>2.0.12</version>
+      <version>2.0.16-d200908262237</version>
     </dependency>
 
     <dependency>