Import database version 1.3.12
Import mysql version 2.1.2
Import build-essential version 1.3.4
Merge branch 'chef-vendor-build-essential'
Import postgresql version 2.2.2
Import aws version 0.100.6
Fix a JDBC connection error

It seems JDBC will close the idle connection which cause an
connection error. In this commit, we try to validate DB connection
before using it.