Mike Fleetwood authored Mar 29, 2021 and Curtis Gedak committed Apr 03, 2021

Since changes for issue #131 "GParted hangs when non-named device is
hung" FS_Info cache is initialised, cleared and loaded via one call to
load_cache_for_paths().  It runs blkid for named or found disk devices
and associated found partitions from /proc/partitions, rather than
running blkid and letting it report for all block devices.

To avoid the possibility of using blkid on an encryption mapping on a
non-specified and possibly hung block device GParted can't just specify
all encryption mappings.  Instead only encryption mappings which belong
to the above identified block devices should be probed.  That requires
identifying LUKS encryption data in the block devices first so will
require subsequently loading additional data into the FS_Info cache and
running blkid again.

To accommodate this make the FS_Info cache incrementally loadable,
rather than doing everything in a single call to load_cache_for_paths().
Have a separate clear_cache() call which initialises and clears the
cache and make load_cache_for_paths() just run blkid and insert data for
the named paths.

Closes 148 - Encrypted file systems are no longer recognised