test: ha tester: drop unused import

There is no user of File::Path remaining after commit 787b66e
("SimCluster: setup status dir inside new") which was the only user
of remove_tree(). make_path() was not used at all according to git
history.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

src/test/ha-tester.pl

@@ -4,8 +4,6 @@ use strict;
 use warnings;
 use Getopt::Long;
 
-use File::Path qw(make_path remove_tree);
-
 my $opt_nodiff;
 my $opt_nofail;
 my $opt_notestout;