Integrate meta-seconorth-distro/refactor_DISTRO_FEATURES_removal

--

Commit: seco-ne/yocto/layers/meta-seconorth-distro@c738078b

seconorth-wayland: Refactor DISTRO_FEATURES:remove

The Yocto system for appending and removing items form lists executes
the removal as a last step. After a removal an item cannot be
appended.

For the DISTRO_FEATURES this means that the once removed "x11" item
cannot be appended in later steps or dependent layers.

This can be circumvented by the introduction of intermediate variables
or by using such variables.

For example poky defines DISTRO_FEATURES as follows
```
DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT} ${POKY_DEFAULT_DISTRO_FEATURES}"
```
To remove an item from the DISTRO_FEATURES you can instead remove it
form one of the variables i.e. the DISTRO_FEATURES_DEFAULT variable.

Thus remove the `bluetooth` and `x11` items from the
DISTRO_FEATURES_DEFAULT to be able to re-add them to DISTRO_FEATURES
later.

default.xml

@@ -22,7 +22,7 @@
     <project name="meta-freescale.git"              revision="dd98526300937450d741c9b3403799632f417226"  remote="fslc"         path="sources/meta-freescale"            />
     <project name="meta-freescale-distro.git"       revision="fc15f5003043da23212596be7366ae2547c308ad"  remote="fslc"         path="sources/meta-freescale-distro"     />
     <project name="layers/meta-seconorth-machine"   revision="d87f2c9f8fedce1116be36c33bd88616ec65f98a"  remote="seco-ne"      path="sources/meta-seconorth-machine"    />
-    <project name="layers/meta-seconorth-distro"    revision="bcdcb96ee56dac7ae80a675a84db7bb63ff3ad77"  remote="seco-ne"      path="sources/meta-seconorth-distro"     />
+    <project name="layers/meta-seconorth-distro"    revision="c738078b446969e9fa081f3cc66912f4415a193a"  remote="seco-ne"      path="sources/meta-seconorth-distro"     />
     <project name="layers/meta-seconorth-nogplv3"   revision="df1cad973746455b60715b73758fbe9efe80e57d"  remote="seco-ne"      path="sources/meta-seconorth-nogplv3"    />
     <project name="config"                          revision="e055264027aa5f3621d6d4e6c11ce88b252efcd0"  remote="seco-ne"      path=".conf"                              >
         <linkfile dest="setup-environment" src="setup-environment" />