www/grafana4: update and fix bugs

• Update to 4.3.2 [1]
• Fix paths not to include the major version to fix plugin install and keep things uniform [2]
• Correct boot.js seems to be used now [3]

PR: 219639 [1]
PR: 218010 [2]
PR: 219131 [3]
Submitted by: farrokhi [1]
Reported by: Borja Marcos <borjam@sarenet.es> [2]
Reported by: Ari Suutari <ari@stonepile.fi> [3]