Fix dependency.


git-svn-id: https://svn.salilab.org/imp/trunk@17438 e91f8c7b-0e32-4433-a9ac-4502d39a4eab
add missing #include

git-svn-id: https://svn.salilab.org/imp/trunk@17440 e91f8c7b-0e32-4433-a9ac-4502d39a4eab