Revert "add removePackage() to RepositoryInterface"

This reverts commit cfb0d33c4525d30cd5c283d0c6ac4b389e8b3cd7.

Fixes #7634

src/Composer/Repository/RepositoryInterface.php

@@ -71,11 +71,4 @@ interface RepositoryInterface extends \Countable
      * @return array[] an array of array('name' => '...', 'description' => '...')
      */
     public function search($query, $mode = 0);
-
-    /**
-     * Removes a package from the registered packages list.
-     *
-     * @param PackageInterface $package
-     */
-    public function removePackage(PackageInterface $package);
 }