[1D] Fixed an uninitialized variable in Domain1D

Cherry-pick of r1997

Author: speth

include/cantera/oneD/Domain1D.h

@@ -48,6 +48,7 @@ class Domain1D
     Domain1D(size_t nv=1, size_t points=1,
              doublereal time = 0.0) :
         m_rdt(0.0),
+        m_nv(0),
         m_time(time),
         m_container(0),
         m_index(npos),