Port provisioner scripts to updated framework

Updates all the example provisioner scripts to use the new functions
exposed by the VMBuilder class as an illustration of how best to use
them.

Also adds a wrapper fail() handler to ensure the cleanup of the script,
as well as the global cleanup, are run on an exception.

api-daemon/provisioner/examples/script/1-noop.py

@@ -31,6 +31,20 @@
 # function is provided in context of the example; see the other examples for
 # more potential uses.
 
+# Within the VMBuilderScript class, several helper functions are exposed through
+# the parent VMBuilder class:
+#  self.log_info(message):
+#    Use this function to log an "informational" message instead of "print()"
+#  self.log_warn(message):
+#    Use this function to log a "warning" message
+#  self.log_err(message):
+#    Use this function to log an "error" message outside of an exception (see below)
+#  self.fail(message, exception=<ExceptionClass>):
+#    Use this function to bail out of the script safely instead if raising a
+#    normal Python exception. You may pass an optional exception class keyword
+#    argument for posterity in the logs if you wish; otherwise, ProvisioningException
+#    is used. This function implicitly calls a "self.log_err" with the passed message
+
 # Within the VMBuilderScript class, several common variables are exposed through
 # the parent VMBuilder class:
 #  self.vm_name: The name of the VM from PVC's perspective
@@ -132,9 +146,8 @@
 # since they could still do destructive things to /dev and the like!
 
 
-# This import is always required here, as VMBuilder is used by the VMBuilderScript class
-# and ProvisioningError is the primary exception that should be raised within the class.
-from pvcapid.vmbuilder import VMBuilder, ProvisioningError
+# This import is always required here, as VMBuilder is used by the VMBuilderScript class.
+from pvcapid.vmbuilder import VMBuilder
 
 
 # The VMBuilderScript class must be named as such, and extend VMBuilder.