Allow rtf conversion to pdf as it is available in Libre Office

src/OfficeConverter/OfficeConverter.php

@@ -199,7 +199,7 @@ private function getAllowedConverter($extension = null)
             'Jpg'  => ['pdf'],
             'Jpeg' => ['pdf'],
             'Jfif' => ['pdf'],
-            'rtf'  => ['docx', 'txt']
+            'rtf'  => ['docx', 'txt', 'pdf']
         ];
 
         if ($extension !== null) {
@@ -228,10 +228,10 @@ private function exec($cmd, $input = '')
         // Cannot use $_SERVER superglobal since that's empty during UnitUnishTestCase
         // getenv('HOME') isn't set on Windows and generates a Notice.
         if ($this->prefixExecWithExportHome) {
-          $home = getenv('HOME');
-          if (!is_writable($home)) {
-              $cmd = 'export HOME=/tmp && ' . $cmd;
-          }
+            $home = getenv('HOME');
+            if (!is_writable($home)) {
+                $cmd = 'export HOME=/tmp && ' . $cmd;
+            }
         }
         $process = proc_open($cmd, [0 => ['pipe', 'r'], 1 => ['pipe', 'w'], 2 => ['pipe', 'w']], $pipes);
         fwrite($pipes[0], $input);