Update Subversion packages to the latest release, v1.9.6.

Signed-off-by: Val Kulkov <val.kulkov@gmail.com>

Compile tested: LEDE HEAD

If unixodbc package is present in the environment, subversion
fails to compile due to missing dependencies.

Fixes the dependency on unixodbc if unixodbc package is selected.

Signed-off-by: Val Kulkov <val.kulkov@gmail.com>

Compile tested: ar71xx
Run tested: ar71xx

Signed-off-by: Val Kulkov <val.kulkov@gmail.com>

Bring back Subversion from oldpackages and update to the latest version.
Create prerm script to stop subversion server and remove init script
on uninstall.

Signed-off-by: Donald Rumata <donald.rumata@gmail.com>