Remove oc_obt from server build.
Remove oc_obt from server build.

oc_obt.c requires client functions. Hence,
drop it from the server-only libraries.
Signed-off-by: Andreas Zisowsky <0f8ec8760f6bbf76e7fa9ba97460a7a7c7a7e80e@lynxtechnology.com>
Change-Id: I2f145d82db84b3b39e0ec6bf9c54e217126f21d9
Reviewed-on: https://gerrit.iotivity.org/gerrit/23059
Reviewed-by: Kishen Maloor <c62ddea3cd661a9268bff15f07fc2229cdc9ac02@intel.com>
Tested-by: Kishen Maloor <c62ddea3cd661a9268bff15f07fc2229cdc9ac02@intel.com>

iotivity/iotivity-constrained,iotivity/iotivity-constrained,iotivity/iotivity-constrained,iotivity/iotivity-constrained