Fix table rotate conversion to 2.0 format

The old code did create invalid documents, since the space between the rotate
flag dn the previous flag was removed.
(cherry picked from commit b0664e0c98)

lib/lyx2lyx/lyx_2_1.py

@@ -911,7 +911,7 @@ def revert_cell_rotation(document):
           document.body[i] = rgx.sub('', document.body[i])
         elif value == "90":
           rgx = re.compile(r' rotate="[^"]+?"')
-          document.body[i] = rgx.sub('rotate="true"', document.body[i])
+          document.body[i] = rgx.sub(' rotate="true"', document.body[i])
         else:
           rgx = re.compile(r' rotate="[^"]+?"')
           load_rotating = True

status.20x

@@ -49,6 +49,8 @@ What's new
 
 - Fix use math package settings conversion from 2.0 to 2.1 format (bug 9069).
 
+- Fix table cell rotation conversion from 2.1 to 2.0 format.
+
 
 * DOCUMENT INPUT/OUTPUT