Avoid stopping fs.watchFile pollers when rewatching.
Avoid stopping fs.watchFile pollers when rewatching.

Calling unwatchFile may result in stopping the watcher before watchFile is
called, which then restarts it. This temporary stoppage appears to cause
change events to be missed sometimes. In particular, preventing this
stop/start with the acrobatics in this commit seems to fix recent
compiler-plugins.js test failures.

Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor