Fix development environment installation docs
Fix development environment installation docs

There is no need to install npm package - it is included in
nodejs package

Change-Id: I318c832dcdeea6ab3b8cb7d2f0f4b5f094301f19

eayunstack/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,stackforge/fuel-web,huntxu/fuel-web,huntxu/fuel-web,huntxu/fuel-web,stackforge/fuel-web,stackforge/fuel-web