Always run asnyc if the workspace tree is locked

Setting a classpath container to a project while the workspace tree is
locked has the effect that the container is updated but the project is
not build at all.

This overrides the hint to run async in such case to make sure the
project is build appropriately.

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PluginModelManager.java

@@ -37,6 +37,7 @@
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.Adapters;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.ILog;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.MultiStatus;
@@ -384,7 +385,7 @@ private void updateAffectedEntries(StateDelta delta, boolean runAsynch) {
 				index++;
 			}
 			// TODO Consider always running in a job - better reporting and cancellation options
-			if (runAsynch) {
+			if (runAsynch || ResourcesPlugin.getWorkspace().isTreeLocked()) {
 				// We may be in the UI thread, so the classpath is updated in a job to avoid blocking (bug 376135)
 				fUpdateJob.add(projects, containers);
 				fUpdateJob.schedule();
@@ -393,6 +394,7 @@ private void updateAffectedEntries(StateDelta delta, boolean runAsynch) {
 				try {
 					JavaCore.setClasspathContainer(PDECore.REQUIRED_PLUGINS_CONTAINER_PATH, projects, containers, null);
 				} catch (JavaModelException e) {
+					ILog.get().error("Setting classpath containers failed!", e); //$NON-NLS-1$
 				}
 			}
 		}