Fix bridge-method-injector IllegalArgumentException

```
[ERROR] Failed to execute goal com.infradna.tool:bridge-method-injector:1.13:process (default) on project jenkins-core: Failed to process @WithBridgeMethods: Failed to process /home/tiste/dev/tmp/2017-03-29T23h05m22+0200-jenkins-core/jenkins/jenkins/core/target/classes/hudson/model/AbstractItem.class: IllegalArgumentException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal com.infradna.tool:bridge-method-injector:1.13:process (default) on project jenkins-core: Failed to process @WithBridgeMethods
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Failed to process @WithBridgeMethods
        at com.infradna.tool.bridge_method_injector.ProcessMojo.execute(ProcessMojo.java:68)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
        ... 20 more
Caused by: java.io.IOException: Failed to process /home/tiste/dev/tmp/2017-03-29T23h05m22+0200-jenkins-core/jenkins/jenkins/core/target/classes/hudson/model/AbstractItem.class
        at com.infradna.tool.bridge_method_injector.MethodInjector.handle(MethodInjector.java:106)
        at com.infradna.tool.bridge_method_injector.ProcessMojo.execute(ProcessMojo.java:65)
        ... 22 more
Caused by: java.lang.IllegalArgumentException
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:170)
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:153)
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:424)
        at com.infradna.tool.bridge_method_injector.MethodInjector.handle(MethodInjector.java:74)
        ... 23 more
[ERROR]

```