Fixes regarding memory management

Fixes assorted issues identified by valgrind.

src/request_body_processor/multipart.h

@@ -54,13 +54,18 @@ struct MyEqual {
 
 class MultipartPart {
  public:
-     MultipartPart()
+    MultipartPart()
      : m_type(MULTIPART_FORMDATA),
      m_tmp_file_fd(0),
      m_tmp_file_size(0),
      m_offset(0),
      m_length(0) { }
 
+    ~MultipartPart () {
+        m_headers.clear();
+        m_value_parts.clear();
+    }
+
     /* part type, can be MULTIPART_FORMDATA or MULTIPART_FILE */
     int m_type;