Enable to run on ROS Melodic

[youtalk]

Solved AutonomyLab/create_robot#54

When I used this package on Ubuntu 18.04 and ROS Melodic, I had the same problem above.

roslaunch ca_driver create_2.launch
...
[ INFO] [1549365785.956563724]: [CREATE] "CREATE_2" selected
[create::Serial] failed to receive data from Create. Check if robot is powered!
[create::Create] retrying to establish serial connection...
[create::Serial] serial error - Operation canceled
[create::Serial] failed to receive data from Create. Check if robot is powered!
[create::Create] retrying to establish serial connection...
[create::Serial] serial error - Operation canceled
...

This PR solves it based on AutonomyLab/create_robot#54 (comment)

[lopsided98]

What does d2cc4b9 fix? I would recommend adding more explanation to the commit message. In particular, why was 0.1 chosen?

[lopsided98]

I don't currently have ROS setup on my Create, so I can't test this. I might get it running again in the next few weeks, but I'm not sure I'll have time.

[youtalk]

@lopsided98 I'm sorry but d2cc4b9 was my mistake to push. I reverted the commit.

[jacobperron]

@youtalk Thanks for the patch. I'll try to set aside some time to test it this week and I can work on a release for Melodic.

[komeihasegawa]

This worked fine with my Ubuntu18.04, ROS Melodic, and Create1.