Enable transferring of attribute using command 'repo manifest -o -'

'upstream' attribute is now transferred to the new manifest xml
that is created when using command 'repo manifest -o -'.

Manifest help is updated for the attributes 'sync-c','sync-s' and
'sync-j'.

Bug: Issue 164
Change-Id: If63f781e91d25c5b5b5ea0696b0c04337b0a686a
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index f187bfa..28a21bb 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -137,14 +137,14 @@
 this value. If this value is not set, projects will use `revision`
 by default instead.
 
-Attribute `sync_j`: Number of parallel jobs to use when synching.
+Attribute `sync-j`: Number of parallel jobs to use when synching.
 
-Attribute `sync_c`: Set to true to only sync the given Git
+Attribute `sync-c`: Set to true to only sync the given Git
 branch (specified in the `revision` attribute) rather than the
-whole ref space.  Project elements lacking a sync_c element of
+whole ref space.  Project elements lacking a sync-c element of
 their own will use this value.
 
-Attribute `sync_s`: Set to true to also sync sub-projects.
+Attribute `sync-s`: Set to true to also sync sub-projects.
 
 
 Element manifest-server
@@ -232,11 +232,11 @@
 If the project has a parent element, the `name` and `path` here
 are the prefixed ones.
 
-Attribute `sync_c`: Set to true to only sync the given Git
+Attribute `sync-c`: Set to true to only sync the given Git
 branch (specified in the `revision` attribute) rather than the
 whole ref space.
 
-Attribute `sync_s`: Set to true to also sync sub-projects.
+Attribute `sync-s`: Set to true to also sync sub-projects.
 
 Attribute `upstream`: Name of the Git branch in which a sha1
 can be found.  Used when syncing a revision locked manifest in
diff --git a/manifest_xml.py b/manifest_xml.py
index fdc3177..3517c15 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -261,6 +261,8 @@
         revision = self.remotes[remoteName].revision or d.revisionExpr
         if not revision or revision != p.revisionExpr:
           e.setAttribute('revision', p.revisionExpr)
+        if p.upstream and p.upstream != p.revisionExpr:
+          e.setAttribute('upstream', p.upstream)
 
       for c in p.copyfiles:
         ce = doc.createElement('copyfile')