Fixing Performance data in check_snmp_time.pl

# my $local_timestring = time2str("%Y-%m-%e_%T", $local_timestamp);
# my $remote_timestring = time2str("%Y-%m-%e_%T", $remote_timestamp);
my $local_timestring = time2str("%Y-%m-%d_%T", $local_timestamp);
my $remote_timestring = time2str("%Y-%m-%d_%T", $remote_timestamp);