project structure dialog: fix double disposal of newly created libraries (IDEA-196008)

Such libraries will be disposed in getLibrariesModifiableModel().removeLibrary(library) call.

java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/projectRoot/LibrariesModifiableModel.java

@@ -86,9 +86,6 @@ public class LibrariesModifiableModel implements LibraryTableBase.ModifiableMode
 
     if (existingLibrary == library) {
       myRemovedLibraries.add(library);
-    } else {
-      // dispose uncommitted library
-      Disposer.dispose(library);
     }
   }