Merge "adb: replacing fs_mgr_read_fstab() with fs_mgr_read_fstab_default()"

// Returns the device used to mount a directory in the fstab.

static std::string find_fstab_mount(const char* dir) {

    std::string fstab_filename = "/fstab." + android::base::GetProperty("ro.hardware", "");

    struct fstab* fstab = fs_mgr_read_fstab(fstab_filename.c_str());

    struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab, dir);

    std::string dev = rec ? std::string(rec->blk_device) : "";

    fs_mgr_free_fstab(fstab);

    return dev;

    std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),

                                                               fs_mgr_free_fstab);

    struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab.get(), dir);

    return rec ? rec->blk_device : "";

}

// The proc entry for / is full of lies, so check fstab instead.