WL#11854: clean up stuff related to build options, obsolete xmysqlnd module

- fix package.xml

Author: marinesovitch

package.xml

@@ -167,7 +167,6 @@ The X DevAPI introduces a new, modern and easy-to-learn way to work with your da
    <file name="php_mysqlx.h" role="src" />
    <file name="php_mysqlx_ex.cc" role="src" />
    <file name="php_mysqlx_ex.h" role="src" />
-   <file name="php_xmysqlnd.h" role="src" />
    <file name="product_data.txt" role="doc" />
    <file name="protobuf_api.h" role="src" />
    <dir name="messages">