PyUtilib==5.2.3601
Pyomo==4.2.10784
nose==1.3.7
ply==3.8
six==1.10.0
testfixtures==4.8.0
sympy

PyUtilib==5.2.3601
Pyomo==4.2.10784
nose==1.3.7
ply==3.8
six==1.10.0
testfixtures==4.8.0
sympy==1.0

Make the dependency on sympy be a version-pinned dependency
Make the dependency on sympy be a version-pinned dependency

All the other existing dependencies are version-pinned to ensure
reproducibility, so make the recently-added dependency on sympy be
version-pinned too for the same reason and for consistency.
