Update boot.js
removed newline
another suggestion

in case of equal versions, use the incoming and replace the existing.
prerelease matters

incoming 3.7.2 loses against existing 3.7.2
incoming 3.7.2-prerelease loses against existing 3.7.2
incoming 3.7.2-prerelease wins against existing 3.7.2-prerelease
Update boot.js
Update boot.js

if major, minor and patch are equal, the incoming wins.
Merge pull request #1249 from felixhayashi/patch-1

make checkVersions consider build version