If objects or executables did not contain any RPATH, grep would return
nonzero, and the whole stage comparison loop would unexpectedly exit.
Fix this by checking the grep result explicitly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242722 91177308-0d34-0410-b5e6-96231b3b80d8
