Building a lib example causes the lib_ to apear twice in the manifest

[TDW89]

The lib examples depend on the lib they are in for example with lib_xua the first item is the example depending on it's parent repo then the last item is that repo and it's dependencies

Name                    | Location                                        | Branch/tag             | Changeset                                  | Depends_on
------------------------+-------------------------------------------------+------------------------+--------------------------------------------+------------------------------
lib_xua                   [email protected]:xmos/lib_xua.git                   develop                  c4da4c5653460fe82c55c39265c39ffc5764b3f4     lib_xua(HEAD)
...
...
lib_xua                   [email protected]:xmos/lib_xua.git                   develop                  c4da4c5653460fe82c55c39265c39ffc5764b3f4     lib_adat(v1.2.0), lib_locks(v2.2.0), lib_logging(v3.2.0), lib_mic_array(v4.6.0), lib_spdif(v6.1.0), lib_sw_pll(v2.2.0), lib_xassert(v4.2.0), lib_xud(v2.3.1)

[xross]

@danielpieczko this is probably not the end of the world but would be nice to fix if its a quick one? I guess its a test hole too.

[danielpieczko]

I'll have a look to see if it's a simple fix - we haven't converted any existing library examples to XCommon CMake, so that's why we haven't hit this before.

[danielpieczko]

I don't think this is simple to fix, so we'll have to leave this for a later release.