Revert "[FIXED JENKINS-21486] Merged #2172: enforce plugin dependencies."

This reverts commit fa39668b81, reversing
changes made to be9bc0dba5.

core/src/main/java/hudson/PluginManager.java

@@ -679,8 +679,7 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
         // so existing plugins can't be depending on this newly deployed one.
 
         plugins.add(p);
-        if (p.isActive())
-            activePlugins.add(p);
+        activePlugins.add(p);
         synchronized (((UberClassLoader) uberClassLoader).loaded) {
             ((UberClassLoader) uberClassLoader).loaded.clear();
         }