[glibc] Do not prefix RPATHs under /home. Contributes to JB#46168
Scratchbox2 uses the --rpath-prefix option to make the linker search for required libraries under the target rootfs. Packages that run their own binaries as a build step may use RPATH to resolve dependencies located under the build tree - such RPATHs must not be redirected under the target rootfs. It is a common assumption in Scratchbox2 that builds happen under user's home directory.