Fix bug with listing of available plugins when last plugin of previous type was in the same library as the first plugin of a new type.   Would cause some plugins to be unlisted.
Fix bug with listing of available plugins when last plugin of previous type was in the same
library as the first plugin of a new type.   Would cause some plugins to be unlisted.

kbrock/graphviz,jho1965us/graphviz,tkelman/graphviz,kbrock/graphviz,ellson/graphviz,kbrock/graphviz,jho1965us/graphviz,ellson/graphviz,tkelman/graphviz,MjAbuz/graphviz,pixelglow/graphviz,jho1965us/graphviz,MjAbuz/graphviz,BMJHayward/graphviz,MjAbuz/graphviz,MjAbuz/graphviz,pixelglow/graphviz,tkelman/graphviz,jho1965us/graphviz,kbrock/graphviz,BMJHayward/graphviz,BMJHayward/graphviz,pixelglow/graphviz,kbrock/graphviz,jho1965us/graphviz,jho1965us/graphviz,BMJHayward/graphviz,ellson/graphviz,BMJHayward/graphviz,jho1965us/graphviz,MjAbuz/graphviz,BMJHayward/graphviz,ellson/graphviz,tkelman/graphviz,ellson/graphviz,tkelman/graphviz,pixelglow/graphviz,pixelglow/graphviz,MjAbuz/graphviz,kbrock/graphviz,MjAbuz/graphviz,ellson/graphviz,MjAbuz/graphviz,MjAbuz/graphviz,tkelman/graphviz,BMJHayward/graphviz,MjAbuz/graphviz,jho1965us/graphviz,ellson/graphviz,ellson/graphviz,jho1965us/graphviz,BMJHayward/graphviz,pixelglow/graphviz,tkelman/graphviz,kbrock/graphviz,BMJHayward/graphviz,tkelman/graphviz,tkelman/graphviz,ellson/graphviz,kbrock/graphviz,MjAbuz/graphviz,kbrock/graphviz,pixelglow/graphviz,kbrock/graphviz,pixelglow/graphviz,tkelman/graphviz,jho1965us/graphviz,pixelglow/graphviz,ellson/graphviz,BMJHayward/graphviz,pixelglow/graphviz,kbrock/graphviz,BMJHayward/graphviz,tkelman/graphviz,jho1965us/graphviz,ellson/graphviz,pixelglow/graphviz