This mel procedure gets rid of gaps in follicle connections for
selected hair systems. Dependancy graph array attributes can be
sparce, which means that there can be elements in the middle of the
array that are unused. This routine closes up the gaps by
reassigning the connected indices. Typically hair system input
connections will have gaps if one has deleted some of the follicles
at some point. In Maya 7.0 and later such sparce connections should
be harmless, although they had caused problems in earlier versions.