Fix conversion of per node stonith parameters

This converts the per node stonith parameters from Chef::Node::Attribute to a
"normal" ruby hash when stripping the domain from the node names. It seems
assigning a hash of Chef::Node::Attribute objects to the node attributes
doesn't work. When accessing the values later on (in pacemaker::stonith) they
just evaluated to nil.

https://bugzilla.novell.com/show_bug.cgi?id=887244
(cherry picked from commit b92ca6c8a3c8c9bfe19bd0faff6d272680fa6fde)
Fix extraction of stonith parameter from parameter string

Pacemaker::Resource.extract_hash() is written to extract things from a complete
CIB object definition. Therefore it rightfully expects whitespaces before the
data_type ("params" in this case). So we just add those here to make the string
parsable by extract_hash.

https://bugzilla.novell.com/show_bug.cgi?id=887244
(cherry picked from commit ca84efd4ab629ac975e4572b96e0737ce0340bda)