Fix bootchart2 never stopping on non-GUI operating systems with systemd.

This fixes a regression introduced in 56a638ace1d, where the systemd files
were renamed to use the bootchart2 name, but their dependencies on each other
were not updated (so bootchart2.service still referred to the now nonexistant
bootchart-done.timer instead of bootchart2-done.timer.)

Signed-off-by: Max Eliaser <max.eliaser@intel.com>
Rename systemd .service.in/.timer.in files to use bootchart2 name.

This does not make any functional difference, but brings the file names in the
working directory in line with the file names used in the root filesystem. So,
for example, /usr/lib/systemd/system/bootchart2.service now corresponds to
bootchart2.service.in instead of bootchart.service.in.

Signed-off-by: Max Eliaser <max.eliaser@intel.com>