Device initialization is calling plugin open

[ddeboni]

There is an issue with initialization of plugins. For instance, if any of the
PI devices listed in the configuration file fail to initialize, then the whole
thing fails (even though you aren¹t making a call to these devices).
There really shouldn¹t be a connection attempt made until an actual
node is queried.

A work around on Shepard for instance is to copy the shepard-plat.xml
config file and change any nodes that you do not want included to be
dummy devices (there should be a few downed nodes defined as such
already). Better yet, if you are doing single node, copy the shepard-node.xml
file and change it to the node number you want in the device initialization string.

[ddeboni]

We now call initialize once but open only on each handles first call