Use 'blkid -p' instead of lsblk to get device's FS type
Use 'blkid -p' instead of lsblk to get device's FS type

'blkid -p' bypasses the cache and thus gives us up to date
results. Unfortunately, it exits with the code 2 when there's no
signature on the device so we need to use our customized function
to run it.

rhinstaller/libblockdev,rhinstaller/libblockdev,rhinstaller/libblockdev