Added a warning in the documentation about manage_dir when selecting an alternate directory for authorized_keys

Signed-off-by: Brian Coca <briancoca+ansible@gmail.com>

the sysctl command. Calling sysctl should also not be true by default

hostname module was lacking support for Scientific Linux, this commit adds it.

All modules should be using /usr/bin/python in the shebang as ansible_python_interpreter processes this (see FAQ).
Fixing for standardization purposes.

and add a sysctl_set parameter to manage the values in /proc

/etc/rc.conf.local is the preferred location for system-specific
startup configuration, and /usr/local/etc/rc.conf generally isn’t used.

see:
http://www.freebsd.org/doc/handbook/configtuning-core-configuration.html

Adding support for detecting RHEV Hypervisor in ansible_virtualization_type