deal with ignoreinode config setting

Improve handling of directory special remotes with importtree=yes whose
ignoreinode setting has been changed. (By either enableremote or by
upgrading to commit 3e2f1f73cb.)

When getting a file from such a remote, accept the content that would have
been accepted with the previous ignoreinode setting.

After a change to ignoreinode, importing a tree from the remote will
re-import and generate new content identifiers using the new config. So
when ignoreinode has changed to no, the inodes will be learned, and after
that point, a change in an inode will be detected as a change. Before
re-importing, a change in an inode will be ignored, as it was before the
ignoreinode change. This seems acceptble, because the user can re-import
immediately if they urgently need to add inodes. And if not, they'll
do it sometime, presumably, and the change will take effect then.

Sponsored-by: Erik Bjäreholt on Patreon

Utility/InodeCache.hs

@@ -32,6 +32,7 @@ module Utility.InodeCache (
 	inodeCacheToMtime,
 	inodeCacheToEpochTime,
 	inodeCacheEpochTimeRange,
+	replaceInode,
 
 	SentinalFile(..),
 	SentinalStatus(..),
@@ -125,6 +126,10 @@ inodeCacheEpochTimeRange i =
 	let t = inodeCacheToEpochTime i
 	in (t-1, t+1)
 
+replaceInode :: FileID -> InodeCache -> InodeCache
+replaceInode inode (InodeCache (InodeCachePrim _ sz mtime)) =
+	InodeCache (InodeCachePrim inode sz mtime)
+
 {- For backwards compatability, support low-res mtime with no
  - fractional seconds. -}
 data MTime = MTimeLowRes EpochTime | MTimeHighRes POSIXTime