9ce758a3d2
This is similar to recently introduced assert_job_exists(). It will
throws an exception whenever a node is missing and further customize the
exception messages.
Replace an occurence of:
if not self.node_exists(name):
raise JenkinsException('node[%s] already exists' % (name))
By:
self.assert_node_exists(name, 'node[%s] already exists')
Change-Id: Ia2e91843b353c02fb19290eadbbb83db8d2a3124