Merge "Check if sandbox is prepared before mounting pkg specific dirs."

static void PreparePkgSpecificDirs(const std::vector<std::string>& packageNames,

                                   const std::vector<std::string>& volumeLabels,

                                   bool mountAllObbs, userid_t userId, fail_fn_t fail_fn) {

    if (volumeLabels.size() > 0) {

        std::string sandboxDataDir = StringPrintf("/storage/%s", volumeLabels[0].c_str());

        if (volumeLabels[0] == "emulated") {

            StringAppendF(&sandboxDataDir, "/%d", userId);

        }

        StringAppendF(&sandboxDataDir, "/Android/data/%s", packageNames[0].c_str());

        struct stat sb;

        if (TEMP_FAILURE_RETRY(lstat(sandboxDataDir.c_str(), &sb)) == -1) {

            if (errno == ENOENT) {

                ALOGD("Sandbox not fully prepared for %s", sandboxDataDir.c_str());

                return;

            } else {

                fail_fn(CREATE_ERROR("Failed to lstat %s: %s",

                                     sandboxDataDir.c_str(), strerror(errno)));

            }

        }

    }

    for (auto& label : volumeLabels) {

        std::string mntSource = StringPrintf("/mnt/runtime/write/%s", label.c_str());

        std::string mntTarget = StringPrintf("/storage/%s", label.c_str());