Needs to explicitly set the classloader.

Or else, classes from this plugin fails to resolve.

-------------------------
org.jvnet.hudson.reactor.ReactorException: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Script1.groovy: 32: unable to resolve class hudson.security.LDAPSecurityRealm.AuthoritiesPopulatorImpl
 @ line 32, column 1.
   import hudson.security.LDAPSecurityRealm.AuthoritiesPopulatorImpl
   ^

1 error

    at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:246)
    at jenkins.InitReactorRunner.run(InitReactorRunner.java:43)
    at jenkins.model.Jenkins.executeReactor(Jenkins.java:885)
    at jenkins.model.Jenkins.<init>(Jenkins.java:790)
    at hudson.model.Hudson.<init>(Hudson.java:81)
    at hudson.model.Hudson.<init>(Hudson.java:77)
    at hudson.WebAppMain$2.run(WebAppMain.java:217)
Caused by: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Script1.groovy: 32: unable to resolve class hudson.security.LDAPSecurityRealm.AuthoritiesPopulatorImpl
 @ line 32, column 1.
   import hudson.security.LDAPSecurityRealm.AuthoritiesPopulatorImpl
   ^

1 error

    at org.codehaus.groovy.control.ErrorCollector.failIfErrors(ErrorCollector.java:302)
    at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:858)
    at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:548)
    at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:497)
    at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:306)
    at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:287)
    at groovy.lang.GroovyShell.parseClass(GroovyShell.java:731)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:743)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:723)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:790)
    at hudson.util.spring.BeanBuilder.parse(BeanBuilder.java:133)
    at hudson.security.LDAPSecurityRealm.createSecurityComponents(LDAPSecurityRealm.java:359)
    at hudson.security.SecurityRealm.getSecurityComponents(SecurityRealm.java:398)
    at hudson.security.HudsonFilter.reset(HudsonFilter.java:134)
    at jenkins.model.Jenkins.setSecurityRealm(Jenkins.java:1960)
    at jenkins.model.Jenkins$17.run(Jenkins.java:2524)
    at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:146)
    at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
    at jenkins.model.Jenkins$7.runTask(Jenkins.java:874)
    at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
    at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:636)

src/main/java/hudson/security/LDAPSecurityRealm.java

@@ -352,7 +352,7 @@ public class LDAPSecurityRealm extends AbstractPasswordBasedSecurityRealm {
         Binding binding = new Binding();
         binding.setVariable("instance", this);
 
-        BeanBuilder builder = new BeanBuilder();
+        BeanBuilder builder = new BeanBuilder(Jenkins.getInstance().pluginManager.uberClassLoader);
         String fileName = "LDAPBindSecurityRealm.groovy";
         try {
             File override = new File(Jenkins.getInstance().getRootDir(), fileName);