Wrong directory names in service file and bash scripts

[vlandrei]

Description

Following the install instructions for the USRP server, the user is prompted to enable the rpc-server service.
Running systemctl enable rpc-server.service, restarting and then checking the status via systemctl status rpc-server.service yields in failed (Result: exit-code).

This is due to wrong directory names in both rpc-server.service and start_usrp_server.bash. There, the path to the python executables is given as /home/root/usrp_uhd_api/ which does not exist. I suspect this is because usrp_uhd_api/ was the former name of usrp_uhd_wrapper.

Workaround

Replacing /home/root/usrp_uhd_api/ with $INSTALL_DIR/usrp_uhd_wrapper, where $INSTALL_DIR is the directory where the repo was cloned, seems to solve this. Is this the correct solution? If yes, I can submit a pull request and update the docs accordingly.

Other than that, great job on the wrapper!