Fix check_unsecure.sh to pass shellcheck

tools/run_tests/sanity/check_unsecure.sh

@@ -18,10 +18,10 @@ set -e
 # Make sure that there is no path from known unsecure libraries and targets
 # to an SSL library. Any failure among these will make the script fail.
 
-test `bazel query 'somepath("//:grpc_unsecure", "//external:libssl")' 2>/dev/null | wc -l` -eq 0 || exit 1
-test `bazel query 'somepath("//:grpc++_unsecure", "//external:libssl")' 2>/dev/null | wc -l` -eq 0 || exit 1
-test `bazel query 'somepath("//:grpc++_codegen_proto", "//external:libssl")' 2>/dev/null | wc -l` -eq 0 || exit 1
-test `bazel query 'somepath("//test/cpp/microbenchmarks:helpers", "//external:libssl")' 2>/dev/null | wc -l` -eq 0 || exit 1
+test "$(bazel query 'somepath("//:grpc_unsecure", "//external:libssl")' 2>/dev/null | wc -l)" -eq 0 || exit 1
+test "$(bazel query 'somepath("//:grpc++_unsecure", "//external:libssl")' 2>/dev/null | wc -l)" -eq 0 || exit 1
+test "$(bazel query 'somepath("//:grpc++_codegen_proto", "//external:libssl")' 2>/dev/null | wc -l)" -eq 0 || exit 1
+test "$(bazel query 'somepath("//test/cpp/microbenchmarks:helpers", "//external:libssl")' 2>/dev/null | wc -l)" -eq 0 || exit 1
 
 exit 0