fix: use defined namespace prefix

files/usr/lib/check_mk_agent/plugins/check_rosetta_heartbeat.xml

 <soap:Envelope
 	soap:encodingStyle='http://schemas.xmlsoap.org/soap/encoding/'
-	xmlns:namesp1='http://dps.exlibris.com/'
+	xmlns:dps='http://dps.exlibris.com/'
 	xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'
 	xmlns:soapenc='http://schemas.xmlsoap.org/soap/encoding/'
 	xmlns:xsd='http://www.w3.org/2001/XMLSchema'
 	xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'>
 	<soap:Body>
-		<getHeartBit xmlns='http://dps.exlibris.com/' />
+		<dps:getHeartBit/>
 	</soap:Body>
 </soap:Envelope>