templates: split getgraphnode() body into two functions

getgraphnodecurrent() is checking if the node is currently checked out and
getgraphnodesymbol() is checking properties that have more to do with the
stored data and the DAG.

mercurial/templatekw.py

@@ -392,12 +392,19 b' def showgraphnode(context, mapping):'
     return getgraphnode(repo, ctx)
 
 def getgraphnode(repo, ctx):
+    return getgraphnodecurrent(repo, ctx) or getgraphnodesymbol(ctx)
+
+def getgraphnodecurrent(repo, ctx):
     wpnodes = repo.dirstate.parents()
     if wpnodes[1] == nullid:
         wpnodes = wpnodes[:1]
     if ctx.node() in wpnodes:
         return '@'
-    elif ctx.obsolete():
+    else:
+        return ''
+
+def getgraphnodesymbol(ctx):
+    if ctx.obsolete():
         return 'x'
     elif ctx.isunstable():
         return '*'