Don't escape certain non-ascii characters

[daniloegea]

Description

g_strescape will mess up with utf-8 characters. It happens because all the range from 0x7f to 0xff are escaped by default. The bytes in this range can be found in utf-8 code points so non-ascii strings will end being changed.

This PR adds all the range in the exception list.

For example, the file below:

network:
  renderer: NetworkManager
  wifis:
    wlan0:
      access-points:
        "áááÁÁÁ":
          password: "áéí"
        "normal":
          password: "á\né\tí\rÁ"

will become this (output from netplan get):

network:
  version: 2
  renderer: NetworkManager
  wifis:
    wlan0:
      access-points:
        "\\303\\241\\303\\241\\303\\241\\303\\201\\303\\201\\303\\201":
          auth:
            key-management: "psk"
            password: "\\303\\241\\303\\251\\303\\255"
        "normal":
          auth:
            key-management: "psk"
            password: "\\303\\241\\n\\303\\251\\t\\303\\255\\r\\303\\201"

With the new exceptions it will become:

network:
  version: 2
  renderer: NetworkManager
  wifis:
    wlan0:
      access-points:
        "normal":
          auth:
            key-management: "psk"
            password: "á\\né\\tí\\rÁ"
        "áááÁÁÁ":
          auth:
            key-management: "psk"
            password: "áéí"

Checklist

• Runs make check successfully.
• Retains 100% code coverage (make check-coverage).
• New/changed keys in YAML format are documented.
• (Optional) Adds example YAML for new feature.
• (Optional) Closes an open bug in Launchpad.

[slyon]

Looks fine overall, but we might whitelist some control characters that we don't want to have un-escaped (like DELETE). Can you please clarify on this?

And maybe also add a small unit-test around it, so that we can see the actual characters being used?

[daniloegea]

I removed 0x7f from the list and rebased. I also added a unittest using the wifi password.

[slyon]

Thanks, LGTM!