Fix caching issue

Author: LexManos

src/main/java/net/minecraftforge/installer/actions/PostProcessors.java

@@ -128,6 +128,8 @@ public Set<File> process(File librariesDir, File minecraft, File root, File inst
                                             miss = true;
                                             output.file.delete();
                                         }
+                                    } else {
+                                        miss = true;
                                     }
                                 } catch (IOException e) {
                                     e.printStackTrace();