#4503 (ok 4.0.10.2) Self-XSSes in monitor

[Madhura Jayaratne]

Steps: Monitor -> settings -> add chart -> Chose status variables from radio buttons -> type variable name as '' -> Chose append unit to data values and type '' -> Click 'Add this series'.

Affected versions: 4.0.x, 4.1.x, 4.2.x

Problematic line: server_status_monitor.js L905 & L911 (in QA_4_2) "str += serie.unit ? (', ' + PMA_messages.strUnit + ': ' + serie.unit) : '';" and "$('#seriesPreview').append('- ' + newSeries.label + str + '
');"