Recognize Fedora and XO systems (OLPC) platform

Those platforms aren't recognize by ajenti currently. They are Red Hat like distros.

*Fedora 18*
```
$ uname --all
Linux schoolserver 3.8.4-202.fc18.i686.PAE #1 SMP Thu Mar 21 17:14:12 UTC 2013 i686 i686 i386 GNU/Linux
$ python -c "import platform; print platform.linux_distribution()" 
('Fedora', '18', 'Spherical Cow')
```

*OLPC XO-4*
```
$ uname --all
Linux new-host 3.5.7_xo4-20130308.1209.olpc.66ac429 #1 PREEMPT Fri Mar 8 12:21:27 EST 2013 armv7l armv7l armv7l GNU/Linux
[olpc@new-host ~]$ python -c "import platform; print platform.linux_distribution()" 
('XO-system ', '1', 'build 17) (based on Fedora 18')
```

*OLPC XO-1.75*
```
$ python -c "import platform; print platform.linux_distribution()" 
('OLPC', '13', 'based on Fedora 18')
```

*OLPC XO-1*
```
$ python -c "import platform; print platform.linux_distribution()" 
('OLPC', '4', 'based on Fedora 18')
```