Updated the default location of the configuration file on Windows from
C:\telegraf\telegraf.conf to C:\Program Files\Telegraf\telegraf.conf.
With this change includes updating the directions, including directing
that the executable be put into that same directory. Additionally, as
noted in the instructions, the location of the config file for the
service may be changed by specifying the location with the `-config`
flag at install time.
Dennis Bellinger
Ricard Clau