git-svn: allow UUID to be manually remapped via rewriteUUID

In certain situations it may be necessary to manually remap an svn
repostitory UUID. For example:

                  o--- [git-svn clone]
                 /
[origin svn repo]
                 \
                  o--- [svnsync clone]

Imagine that only "git-svn clone" and "svnsync clone" are made available
to external users. Furthur, "git-svn clone" contains only trunk, and for
reasons unknown, "svnsync clone" is missing the revision properties that
normally provide the origin svn repo's UUID.

A git user who has cloned the "git-svn clone" repo now wishes to use
git-svn to pull in the missing branches from the "synsync clone" repo.
In order for git-svn to get the history correct for those branches,
it needs to know the origin svn repo's UUID. Hence rewriteUUID.

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Acked-by: Eric Wong <normalperson@yhbt.net>
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index 8dbf9d1..5df3059 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -62,6 +62,8 @@
 	Set the 'useSvnsyncProps' option in the [svn-remote] config.
 --rewrite-root=<URL>;;
 	Set the 'rewriteRoot' option in the [svn-remote] config.
+--rewrite-uuid=<UUID>;;
+	Set the 'rewriteUUID' option in the [svn-remote] config.
 --username=<USER>;;
 	For transports that SVN handles authentication for (http,
 	https, and plain svn), specify the username.  For other
@@ -629,6 +631,12 @@
 	the repository with a public http:// or svn:// URL in the
 	metadata so users of it will see the public URL.
 
+svn-remote.<name>.rewriteUUID::
+	Similar to the useSvmProps option; this is for users who need
+	to remap the UUID manually. This may be useful in situations
+	where the original UUID is not available via either useSvmProps
+	or useSvnsyncProps.
+
 svn.brokenSymlinkWorkaround::
 	This disables potentially expensive checks to workaround
 	broken symlinks checked into SVN by broken clients.  Set this
@@ -638,13 +646,14 @@
 	revision fetched.  If unset, 'git svn' assumes this option to
 	be "true".
 
-Since the noMetadata, rewriteRoot, useSvnsyncProps and useSvmProps
+Since the noMetadata, rewriteRoot, rewriteUUID, useSvnsyncProps and useSvmProps
 options all affect the metadata generated and used by 'git svn'; they
 *must* be set in the configuration file before any history is imported
 and these settings should never be changed once they are set.
 
-Additionally, only one of these four options can be used per-svn-remote
-section because they affect the 'git-svn-id:' metadata line.
+Additionally, only one of these options can be used per svn-remote
+section because they affect the 'git-svn-id:' metadata line, except
+for rewriteRoot and rewriteUUID which can be used together.
 
 
 BASIC EXAMPLES