Fix sympy profile to work with sympy 0.7.

Sympy 0.7 no longer supports x,y,z = symbols('xyz').
symbols ('xyz') is now a single symbol 'xyz'.

Change the sympy profile to symbols(x,y,z).

IPython/config/profile/sympy/ipython_config.py

@@ -8,8 +8,8 b" load_subconfig('ipython_config.py', profile='default')"
 lines = """
 from __future__ import division
 from sympy import *
-x, y, z = symbols('xyz')
-k, m, n = symbols('kmn', integer=True)
+x, y, z = symbols('x,y,z')
+k, m, n = symbols('k,m,n', integer=True)
 f, g, h = map(Function, 'fgh')
 """