mq: bail out if a patch appears more than once in the series file.
Closes: #379.
adding baseabort: cannot delete applied patch cNow at: bababseriesstatusNow at: aabseriesstatus1 New patch: a0 baseabort: patch e not at basef4 New patch: f3 New patch: e2 New patch: d1 New patch: a0 base