Fix custom build when openlayers is installed from yarn package manager
Fix custom build when openlayers is installed from yarn package manager

This enhance the procedure to find path of jsdoc binary by checking if the file exists.
It also use 2 possible paths to perform this check, one for npm and the other for yarn.

Close #6633

ahocevar/openlayers,ahocevar/openlayers,adube/ol3,fredj/ol3,stweil/ol3,geekdenz/ol3,oterral/ol3,adube/ol3,thhomas/ol3,geekdenz/ol3,ahocevar/ol3,bjornharrtell/ol3,tschaub/ol3,thhomas/ol3,openlayers/openlayers,geekdenz/ol3,klokantech/ol3,oterral/ol3,openlayers/openlayers,adube/ol3,mzur/ol3,gingerik/ol3,bjornharrtell/ol3,tschaub/ol3,planetlabs/ol3,geekdenz/openlayers,ahocevar/ol3,geekdenz/ol3,stweil/openlayers,geekdenz/openlayers,fredj/ol3,gingerik/ol3,fredj/ol3,gingerik/ol3,stweil/openlayers,ahocevar/openlayers,mzur/ol3,gingerik/ol3,ahocevar/ol3,mzur/ol3,tschaub/ol3,klokantech/ol3,stweil/openlayers,stweil/ol3,oterral/ol3,planetlabs/ol3,fredj/ol3,mzur/ol3,planetlabs/ol3,ahocevar/ol3,planetlabs/ol3,klokantech/ol3,klokantech/ol3,stweil/ol3,geekdenz/openlayers,openlayers/openlayers,thhomas/ol3,stweil/ol3,bjornharrtell/ol3,thhomas/ol3,tschaub/ol3