mono: remove copy of host etc files on install

When the mono package is installed, the autotools installer installs
the /etc/mono files to the target. A post_install hook then copies
over the mono libraries to the target as well as the host /etc/mono
files which overrides the target files. The target specific mono
configuration file (/etc/mono/config) is overridden with the host
settings. This causes mono on the target to be unable to locate target
specific .so files as it overrides the changes enacted by the patches
for the package.

Signed-off-by: Dustin Johnson <dustin.r.johnson@gmail.com>
Tested-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Reviewed-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Acked-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>