No timeout set for URLConnection which can cause build to get stuck

I encountered a release build getting stuck. Stack trace revealed that the culprit was an infinite default timeout in URLConnection.

[INFO] at java.net.URL.openStream(URL.java:1007)
[INFO] at org.apache.maven.plugin.javadoc.JavadocUtil.fetchURL(JavadocUtil.java:742)
[INFO] at org.apache.maven.plugin.javadoc.AbstractJavadocMojo.addLinkArguments(AbstractJavadocMojo.java:2982)
[INFO] at org.apache.maven.plugin.javadoc.AbstractJavadocMojo.addStandardDocletOptions(AbstractJavadocMojo.java:3667)
[INFO] at org.apache.maven.plugin.javadoc.AbstractJavadocMojo.executeReport(AbstractJavadocMojo.java:1548)
[INFO] at org.apache.maven.plugin.javadoc.JavadocJar.execute(JavadocJar.java:182)
[INFO] at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:483)

The simple fix is to call setConnectTimeout and setReadTimeout with some sensible default value (jdk 1.5 methods, so might need to use reflection to preseve jdk 1.4 compatibility).