[BZ 1015334] EAP 6 host controller domain host update results in managed
servers no longer being "manageable"

This commit deprecates 'domainHost' read-only pluginConfiguration property.
Instead new trait called 'Domain Host Name' was introduced.
BaseServerComponent#validateServerAttributes() now also checks for HC name
and if needed re-reads it from host.xml file. When <host name= changes,
deprecated 'domainHost' property does not get updated (since there is no way
from plugin avail code to update pluginConfiguration on server).
BaseServerComponent now handles 'domainHost' in memory, this variable gets
updated on component start or in avail code (when server was DOWN and now is
UP). Managed servers have domain host name as part of resource key, they get
correctly discovered when this change occurs.

(cherry picked from commit f9ef978b72ae6d484a4143990bbc5db8965cc18d)
Signed-off-by: Libor Zoubek <lzoubek@redhat.com>

Conflicts:
	modules/plugins/jboss-as-7/src/main/java/org/rhq/modules/plugins/jbossas7/BaseServerComponent.java
[BZ 1015334] EAP 6 host controller domain host update results in managed
servers no longer being "manageable"

Fixed javadocs, renamed variables. Also made access to ASHostName
synchronized since it's value can be changed from avail thread and is being
read all over other threads. Big change of this commit is getAvailability().
Now we directly read server's name attribute instead of 'launch-type' (which
was probably lets-just-read-something) and in case of failure (making we
just failed to read value, but connection and other stuf is OK) we re'read
<host name from file and try the request again. This approach is more robust
than previous, which was only able to detect the change in case server avail
went from DOWN to UP. Now, we can detect the change anytime.

(cherry picked from commit e8ad09ec4c43149a06efd2be803caa43386ee956)
Signed-off-by: Libor Zoubek <lzoubek@redhat.com>

Conflicts:
	modules/plugins/jboss-as-7/src/main/java/org/rhq/modules/plugins/jbossas7/BaseServerComponent.java
Throw ResultFailedException only in case we really only failed to read
requested attribute but we succeeded to connect and authenticate

this fixes issue introduced by PR23: agent log was incorrectly spammed by
warn avail messages when standalone or domain EAP6 was turned off.

(cherry picked from commit 4bba58bca1e7363c1cba2d777e92a07ace9a1d41)
Signed-off-by: Libor Zoubek <lzoubek@redhat.com>
[as7] properly detect when we fail to read attribute, but still are connected and authenticated

(cherry picked from commit d7d3ce6feff41b766a1f8f1e2580c5789216a779)
Signed-off-by: Libor Zoubek <lzoubek@redhat.com>

Conflicts:
	modules/plugins/jboss-as-7/src/main/java/org/rhq/modules/plugins/jbossas7/BaseComponent.java
fix as7 plugin build issue (caused by previous cherry-picks)