Fix Homebrew Channel /exec bug on webOS 1

[throwaway96]

No description provided.

[throwaway96]

Done in webosbrew#172.

[throwaway96]

Actually not done. On webOS 1, you don't get the base64 output in the response.

webOS 1.4.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"echo test"}'
{"returnValue":true,"error":null,"stdoutString":"test\n","stdoutBytes":"test\n","stderrString":"","stderrBytes":""}

webOS 8.1.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"echo test"}'
{"returnValue":true,"error":null,"stdoutString":"test\n","stdoutBytes":"dGVzdAo=","stderrString":"","stderrBytes":""}```

[throwaway96]

Fixed in webosbrew#178.