fix syntax error in Maintainer: field that confuses UDD & the Tracker

debian/control

 Source: mysql-connector-python
 Section: python
 Priority: optional
-Maintainer: Debian Python Team <team+python@tracker.debian.org>,
+Maintainer: Debian Python Team <team+python@tracker.debian.org>
 Build-Depends: debhelper-compat (= 13),
                dh-sequence-python3,
                default-mysql-server | virtual-mysql-server,