Fixed typo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173478 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/GettingStarted.rst b/docs/GettingStarted.rst
index 7ea5473..048d4a0 100644
--- a/docs/GettingStarted.rst
+++ b/docs/GettingStarted.rst
@@ -655,10 +655,10 @@
   fi
 
   git fetch
-  old_branch=$(git rev-parse --abbrev-ref HEAD)
+  OLD_BRANCH=$(git rev-parse --abbrev-ref HEAD)
   git checkout master 2> /dev/null
   git svn rebase -l
-  git checkout $old_breanch 2> /dev/null
+  git checkout $OLD_BRANCH 2> /dev/null
 
   if [ ! -z $STASH ]; then
       git stash pop >/dev/null