Prune the npm-install task before inserting it
Prune the npm-install task before inserting it

This resulted in a bug where the npm-install task was given
twice and another task was removed.

Xarthisius/girder,adsorensen/girder,Kitware/girder,adsorensen/girder,jbeezley/girder,Kitware/girder,Kitware/girder,Xarthisius/girder,sutartmelson/girder,manthey/girder,girder/girder,adsorensen/girder,sutartmelson/girder,data-exp-lab/girder,kotfic/girder,sutartmelson/girder,girder/girder,Xarthisius/girder,RafaelPalomar/girder,data-exp-lab/girder,adsorensen/girder,adsorensen/girder,RafaelPalomar/girder,Kitware/girder,data-exp-lab/girder,kotfic/girder,kotfic/girder,sutartmelson/girder,RafaelPalomar/girder,girder/girder,jbeezley/girder,girder/girder,jbeezley/girder,Xarthisius/girder,data-exp-lab/girder,kotfic/girder,manthey/girder,data-exp-lab/girder,manthey/girder,jbeezley/girder,manthey/girder,kotfic/girder,sutartmelson/girder,RafaelPalomar/girder,RafaelPalomar/girder,Xarthisius/girder