fix SAE jetty bug: String index out of range

HTTP ERROR 500

Problem accessing /. Reason:

    String index out of range: -11
Caused by:

java.lang.StringIndexOutOfBoundsException: String index out of range:
-11
	at java.lang.String.substring(String.java:1949)
	at java.lang.String.substring(String.java:1916)
	at clojure.core$subs.invoke(core.clj:4516)
	at addrbook.servlet$_service$fn__141.invoke(servlet.clj:1)
	at ring.util.servlet$make_service_method$fn__56.invoke(servlet.clj:126)
	at addrbook.servlet$_service.invoke(servlet.clj:1)
	at addrbook.servlet.service(Unknown Source)
	at
org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:538)
	at
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:47
8)
	at
com.sina.sae.servlet.SaeServletHandler.doHandle(SaeServletHandler.java:4
9)
	at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java
:119)
	at
org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:5
17)
	at
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.
java:225)
	at
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.
java:937)
	at
org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406
)
	at
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.j
ava:183)
	at
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.j
ava:871)
	at
com.sina.sae.webapp.SaeWebAppContext.doScope(SaeWebAppContext.java:166)
	at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java
:117)
	at
org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(Context
HandlerCollection.java:259)
	at
org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollect
ion.java:149)
	at
com.sina.sae.handler.SaeUserInfoHandler.handle(SaeUserInfoHandler.java:1
06)
	at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.ja
va:110)
	at
org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.j
ava:305)
	at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.ja
va:110)
	at org.eclipse.jetty.server.Server.handle(Server.java:346)
	at
org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.jav
a:589)
	at
org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(Ht
tpConnection.java:1048)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:601)
	at
org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:214)
	at
org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:411)
	at
org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPo
int.java:535)
	at
org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoi
nt.java:40)
	at
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.ja
va:529)
	at java.lang.Thread.run(Thread.java:714)