Delete password as per block encryption

Bug: 18151196
Change-Id: Iee0f932c61ff4a309dc2861725b24bf976adb4c7
diff --git a/Ext4Crypt.h b/Ext4Crypt.h
index 68e0fb2..53a26a0 100644
--- a/Ext4Crypt.h
+++ b/Ext4Crypt.h
@@ -12,6 +12,7 @@
 int e4crypt_check_passwd(const char* path, const char* password);
 int e4crypt_get_password_type(const char* path);
 const char* e4crypt_get_password(const char* path);
+void e4crypt_clear_password(const char* path);
 int e4crypt_restart(const char* path);
 int e4crypt_get_field(const char* path, const char* fieldname,
                       char* value, size_t len);