Push gohai metadata

Handle case when gohai command fails
Update metadata sending frequency

send agent checks each 10 minutes
send metadata each 4 hours
Push gohai metadata

Handle case when gohai command fails
Update metadata sending frequency

send agent checks each 10 minutes
send metadata each 4 hours
Update postgresql test to consider new metrics
Merge branch 'tristan/gohai' of github.com:DataDog/dd-agent into tristan/gohai
Review fix of gohai

use dict instead of getattr and stator
Merge pull request #967 from DataDog/tristan/gohai

Push gohai metadata