gconf.bbclass: don't register schemas in the install stage
Previously this was installing schemas in the sysroot, which is wrong for native
packages as nothing should touch the sysroot directly, and even more wrong for
non-native packages as the sysroot is irrelevant.
So, export the environment variable that stops the registration happening at
install time. The postinst script will handle the non-native case, and for the
sysroot I've opened #2648. This isn't a massive problem as nothing to my
knowledge actually installs schemas to the sysroot.
[YOCTO #2245]
Signed-off-by: Ross Burton <ross.burton@intel.com>
