bitbake: fetch2/git: Stop git from triggering fsync() calls

bitbake: fetch2/git: Stop git from triggering fsync() calls

We only ever clone other repositories, if there were a problem such as power
failure, we'd blow away data and rebuild. As such we don't need fsync(). With
filesystems like ext*, the fsync pushes nearly all the data out to disk
which impacts all running processes.

We therefore set a configuration parameter to disable the fsync() calls.

Also fixup a case where basecmd wasn't being used for no good reason.

(Bitbake rev: 0a26abaf3a1e34d556c9375068dd17c879568d0f)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>