Issue cweagans#258: Remove patch report generation (PATCHES.txt).

This is a backport of pull request cweagans#213 for issue cweagans#140.
The two commits from cweagans#213 have been squashed into one.

src/Patches.php

@@ -322,9 +322,6 @@ public function postInstall(PackageEvent $event) {
       }
     }
     $localPackage->setExtra($extra);
-
-    $this->io->write('');
-    $this->writePatchReport($this->patches[$package_name], $install_path);
   }
 
   /**
@@ -426,22 +423,6 @@ protected function isPatchingEnabled() {
     }
   }
 
-  /**
-   * Writes a patch report to the target directory.
-   *
-   * @param array $patches
-   * @param string $directory
-   */
-  protected function writePatchReport($patches, $directory) {
-    $output = "This file was automatically generated by Composer Patches (https://github.com/cweagans/composer-patches)\n";
-    $output .= "Patches applied to this directory:\n\n";
-    foreach ($patches as $description => $url) {
-      $output .= $description . "\n";
-      $output .= 'Source: ' . $url . "\n\n\n";
-    }
-    file_put_contents($directory . "/PATCHES.txt", $output);
-  }
-
   /**
    * Executes a shell command with escaping.
    *