use libstorage-ng to determine whether efibootmgr is available (bsc#937067)

[wfeldt]

Problem

• https://trello.com/c/ZWMQnKom
• https://bugzilla.suse.com/show_bug.cgi?id=937067

EFI detection code is all over the place. Consolidate in one spot. As libstorage-ng is using this as well - rely on libstorage-ng.

Solution

• add Y2Storage::Arch.efibootmgr? method
• Y2Storage::Arch.efiboot? takes LIBSTORAGE_EFI and /etc/install.inf::efi settings into account
• Y2Storage::StorageManager.arch is initialized taking LIBSTORAGE_EFI and /etc/install.inf::efi settings into account

Note

#efibootmgr? and #efiboot? are independent and do not rely on each other (#efiboot? == false does not imply #efibootmgr? == false, for example). This is how it works in libstorage-ng and the sematics are kept here.

See also

• https://github.com/openSUSE/libstorage-ng/pull/846

[coveralls]

Coverage decreased (-0.004%) to 97.741% when pulling e03363c18e6a994e0df1cd0e130ec4d608ff6293 on sw_100 into 3431edf1508f8c736a485e8a024b13998fd94826 on master.

[yast-bot]

:heavy_check_mark: Public Jenkins job #404 successfully finished :heavy_check_mark: Created OBS submit request #937796

[yast-bot]

:heavy_check_mark: Internal Jenkins job #197 successfully finished :heavy_check_mark: Created IBS submit request #260048