failure to load may show up as a LinkageError, instead of ClassNotFoundException if it's one of the dependencies that have failed to load.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@16790 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/ClassicPluginStrategy.java

@@ -202,6 +202,8 @@ public class ClassicPluginStrategy implements PluginStrategy {
                         throw new IOException(className+" doesn't extend from hudson.Plugin");
                     }
                     wrapper.setPlugin((Plugin) o);
+                } catch (LinkageError e) {
+                    throw new IOException2("Unable to load " + className + " from " + wrapper.getShortName(),e);
                 } catch (ClassNotFoundException e) {
                     throw new IOException2("Unable to load " + className + " from " + wrapper.getShortName(),e);
                 } catch (IllegalAccessException e) {