Merge "installd: Avoid potential use of null 'src'." into nyc-dev

bool create_cache_path(char path[PKG_PATH_MAX],

                       const char *src,

                       const char *instruction_set) {

    size_t srclen = strlen(src);

    /* demand that we are an absolute path */

    if ((src == 0) || (src[0] != '/') || strstr(src,"..")) {

    if ((src == nullptr) || (src[0] != '/') || strstr(src,"..")) {

        return false;

    }

    size_t srclen = strlen(src);

    if (srclen > PKG_PATH_MAX) {        // XXX: PKG_NAME_MAX?

        return false;

    }