Updated `netstat` command to minimize its output with `-t` and `-l`
flags.
Refactored regex on `libmachine/provision/utils.go`:`checkDaemonUp` to
avoid `matchNetstatOut` returning `true` when remote machine has a
similar port to dockerPort listening (e.g. dockerPort := 2376 and
remote machine has port 23760 listening).
Refactored `utils_test.go` with more accurate `netstat` output.
Signed-off-by: Tiago Pires <tandrepires@gmail.com>