Amend the jgit.config example for NFSv4 with caching

When using NFSv4 with standard caching, the jgit.config needs to be
amended to be tolerant to the following caching behaviours:

- File attribute caching
- File listing caching
- Negative caching

Amend the example of jgit.config and include all the options typically
needed with a default NFS v4 client.

Release-Notes: Improve jgit.config documentation for NFS v4 caching
Change-Id: I06e6622c8748f5b6c8ce0d256efd18599ccc9cf9

Documentation/config-gerrit.txt

diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index f6dd40a..4796135 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -6306,10 +6306,19 @@
 system-wide and user-global Git configuration for its runtime JGit
 configuration.
 
+[NOTE]
+When using a shared filesystem, such as NFS, the JGit settings need
+to be adjusted for being tolerant to the filesystem attributes caching.
+The example below shows a typical setting with an NFS v4 mount
+with default caching settings.
+
 Sample `etc/jgit.config` file:
 ----
 [core]
-  trustFolderStat = false
+    supportsAtomicFileCreation = false
+    trustFolderStat = false
+    trustLooseRefStat = after_open
+    trustPackedRefsStat = after_open
 ----
 
 [[jgit-gc]]