src/sage/rings/polynomial/multi_polynomial.pyx: sage.libs.giac -> giac

One test in this file use the giac pexpect interface but is tagged
with "needs sage.libs.giac". Now that we have a feature for the giac
executable, "needs giac" is more appropriate.

Author: orlitzky

src/sage/rings/polynomial/multi_polynomial.pyx

@@ -1114,7 +1114,7 @@ cdef class MPolynomial(CommutativePolynomial):
 
         TESTS::
 
-            sage: # needs sage.libs.giac
+            sage: # needs giac
             sage: R.<x,y,z> = GF(101)['e,i'][]
             sage: f = R('e*i') * x + y^2
             sage: f._giac_init_()