ppl/__init__.py: Bump version to 0.8.10rc2

Author: mkoeppe

ppl/__init__.py

@@ -127,7 +127,7 @@
   Remove the _mutable_immutable class.
 """
 
-__version__ = "0.8.10rc1"
+__version__ = "0.8.10rc2"
 
 from .linear_algebra import (
         Variable, Variables_Set, Linear_Expression,