fix #6123 -- there's a script (which I never use) that automates removing package-lock.json; make sure it also deletes node_modules
fix #6123 -- there's a script (which I never use) that automates removing package-lock.json; make sure it also deletes node_modules

sagemathinc/smc,sagemathinc/smc,sagemathinc/smc,sagemathinc/smc