We need the nss libs in our final install always (unless using system-nss libs)
so finally disentangle nss from mozilla because --disable-build-mozilla had the
sideeffect of *not* including the nss libraries in the final install. Which
means that the xml_xmlsec.dll on windows couldn't be loaded due to missing
dependencies.

a) Strip out the nss libs from the pre-builds if those are being used.
b) Strip out the nss libs from the mozilla build itself if that's being used.
c) Don't include the nss libs in the weird mozillaruntime.zip which gets unpacked
    into the install.
d) Package the nss libs directly in scp2 like everything else

Change-Id: Ia89d75cb0c0b83e84e60d0444ffc7997103fbc55