roscpp-core: removed currently unneeded recipe for meta-package roscpp-core

The roscpp-core package is a meta-package. This meta-package and the concept
meta-package in general is not used for any purpose in our layer.

recipes-ros/roscpp-core/roscpp-core_0.3.12.bb

-DESCRIPTION = "Underlying data libraries for roscpp messages"
-SECTION = "devel"
-LICENSE = "BSD"
-LIC_FILES_CHKSUM = "file://package.xml;beginline=8;endline=8;md5=d566ef916e9dedc494f5f793a6690ba5"
-
-DEPENDS = "cpp-common roscpp-serialization roscpp-traits rostime"
-
-require roscpp-core.inc
-
-S = "${WORKDIR}/roscpp_core-${PV}/${ROS_BPN}"