Minor release script fixes.

Change-Id: Ifd0a7f4f584c85d4d9574eca46094b372a8d7aff

scripts/make_release

diff --git a/scripts/make_release b/scripts/make_release
index d5867b3..1634f7c 100755
--- a/scripts/make_release
+++ b/scripts/make_release
@@ -98,7 +98,7 @@
 
 # Don't leave a mess behind.
 rm -rf $TMP
-rm -rf /tmp/sphinx-build/ceres-solver
+rm -rf $DOCS_TMP
 
 # Reminder to upload.
 echo