We must avoid to fork process when starting the Heka daemon because if
we kill the wrapper, the Heka daemon is detached and re-attach to the
init process. This can create several Heka daemon. To avoid this we need
to use exec and avoid the usage of sudo.
Fixes-bug: #1561109
Change-Id: Idbfab2de92b993d1e5124de5bff44c4b09a88bb4