inc/test-eom-align: Fix MMDF-mbox `A' size calculation.
inc/test-eom-align: Fix MMDF-mbox `A' size calculation.

The `...LINESZ' variables are number of bytes, not number of lines, so
MMDF's is now 5 rather than 1.  And the MMDF magic string tops and tails
each email so needs to be subtracted twice, not once like From_'s.
Fixes 8699f1cc.

mcr/nmh,mcr/nmh