convert: fix test-convert-svn-* problems with mtime not changing
The `svn commit` command does not detect changed files unless
their mtime has changed. A quick succession of, for instance,
`svn co ...; echo x >> y; svn ci` can thus lead to the change to y
being ignored.
Edited by pmezard to write in binary mode.
% init foo-base
% create alpha in first repo
adding alpha
% clone foo-base to foo-work
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
% create beta in second repo
adding beta
% create gamma in first repo
adding gamma
% pull into work and merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
% revert to changeset 1 to simulate a failed merge
2 files updated, 0 files merged, 0 files removed, 0 files unresolved