ntp: Deal with /usr/libexec being empty in Yocto master

libexecdir is now a dedicated directory and empty in our ntpd
build. Avoid QA issue of an empty directory not belonging to
anyone. Clean it if it is empty

recipes-bsp/ntp/ntp_4.2.8p1.bb

@@ -101,6 +101,10 @@ do_install_append() {
 
     install -d ${D}${systemd_unitdir}/ntp-units.d
     install -m 0644 ${WORKDIR}/ntpd.list ${D}${systemd_unitdir}/ntp-units.d/60-ntpd.list
+
+    if [ `ls -A ${D}${libexecdir} | wc -l` -eq 0 ]; then
+        rm -rf ${D}${libexecdir}
+    fi
 }
 
 PACKAGES += "ntpdate sntp ${PN}-tickadj ${PN}-utils ${PN}-perl"