This moves the instantiation of the plugin thread objects after the
creation of the deserialiser. Previously, the threads were trying to
access the deserialiser which wasn't initialised yet and were trying to
work with a null pointer.
Coverage remained the same at 51.888% when pulling 5db778ed300dd07fb0075630abfbc34a450c0ea6 on muffix:delay-thread-creation into ebaa8af60af93531c848e4e2b4baf45bc2f92790 on OpenTSDB:master.
This moves the instantiation of the plugin thread objects after the creation of the deserialiser. Previously, the threads were trying to access the deserialiser which wasn't initialised yet and were trying to work with a null pointer.
Resolves: #10