Fixes #10643: Ensure paths are properly expanded when comparing synced folders

Prior to this commit, the docker action would attempt to compare and
validate synced folders based on their string value, rather than their
actual path value. This commit updates that by path expanding the mounts
when comparing a containers synced folders.

plugins/providers/docker/action/compare_synced_folders.rb

@@ -32,14 +32,18 @@ module VagrantPlugins
             fs.each do |_, data|
               invalid = false
               old     = existing.delete(data[:guestpath])
-              invalid = true if !old
+              if !old
+                invalid = true
+              else
+                old = File.expand_path(old)
+              end
 
               if !invalid && old
-                invalid = true if old != data[:hostpath]
+                invalid = true if old != File.expand_path(data[:hostpath])
               end
 
               if invalid
-                invalids[data[:guestpath]] = data[:hostpath]
+                invalids[File.expand_path(data[:guestpath])] = File.expand_path(data[:hostpath])
               end
             end
           end