<bugfix>Expanding port specs deals with differences between descriptor and port signatures</bugfix>
<bugfix>Expanding port specs deals with differences between descriptor and port signatures</bugfix>

Port specs have the format:

 (<identifier>:<name>:<namespace>, ...)

but descriptor shorthand has:

 <identifier>:<namespace>|<name>

Descriptor expansion assumes the second, but we use this for port spec
expansion so now we need to reformat the port spec before sending it
to the descriptor expansion.

core/modules/module_registry.py:
  - ModuleRegistry.expand_port_spec_string: switch format of
    descriptor signature before sending to expand_descriptor_string

celiafish/VisTrails,hjanime/VisTrails,celiafish/VisTrails,minesense/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,celiafish/VisTrails,hjanime/VisTrails,minesense/VisTrails,Nikea/VisTrails,Nikea/VisTrails,celiafish/VisTrails,hjanime/VisTrails,Nikea/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,minesense/VisTrails,minesense/VisTrails