automated: sh-test-lib: add support for /etc/os-release file

/etc/os-release is a standard file in most distro now, [1] and [2].

Let's use it as the default mechanism to detect the distro at run time, and keep
the old mechanisms as fallback.

Also
* defines 'oe-based' name for any known OE based releases, so that we can
adapt test cases accordingly.
* convert the ID name found in /etc/os-release into the one we used to have in
lsb_release (e.g. Ubuntu vs ubuntu, ... ).

[1] https://www.freedesktop.org/software/systemd/man/os-release.html
[2] http://0pointer.de/blog/projects/os-release.html

Change-Id: I1c9e11b449f8532450c8343bc29eb0aeec58c229
Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
diff --git a/automated/lib/sh-test-lib b/automated/lib/sh-test-lib
index 39b65cd..32c481f 100755
--- a/automated/lib/sh-test-lib
+++ b/automated/lib/sh-test-lib
@@ -151,7 +151,10 @@
 }
 
 dist_name() {
-    if [ -x /usr/bin/lsb_release ]; then
+    if [ -f /etc/os-release ]; then
+        # shellcheck disable=SC1091
+        dist=$(. /etc/os-release && echo "${ID}")
+    elif [ -x /usr/bin/lsb_release ]; then
         dist="$(lsb_release -si)"
     elif [ -f /etc/lsb-release ]; then
         # shellcheck disable=SC1091
@@ -166,6 +169,14 @@
         dist="Unknown"
         warn_msg "Unsupported distro: cannot determine distribution name"
     fi
+
+    case "${dist}" in
+        debian) dist="Debian" ;;
+        ubuntu) dist="Ubuntu" ;;
+        fedora) dist="Fedora" ;;
+        centos) dist="CentOS" ;;
+        rpb|rpb-wayland|rpb-eglfs) dist="oe-based" ;;
+    esac
 }
 
 install_deps() {