perl: *.pm files should not have the executable bit

The Git::Mail::Address file added in bd869f6 ("send-email: add and
use a local copy of Mail::Address", 2018-01-05) had the executable bit
set. That bit should not be set for *.pm files. It breaks nothing but
it is redundant and confusing as none of the other files have it and
these files are never executed as stand-alone programs.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar