Mark CVE-2018-7032 as fixed for mr/1.16

The src:mr 1.16 source package was made an empty source package (thus in
particular not containing anymore webcheckout) for transition purposes
to webcheckout. The mr package was not 'taken' over by src:myrepos thus
this transtition solution.

Given 1.16 removed all scripts, the issue is not present source-wise in
jessie.