Fix gcc 8.1 warning: "maybe use uninitialized"
diff --git a/test/stdvector.cpp b/test/stdvector.cpp
index 9a70408..18de240 100644
--- a/test/stdvector.cpp
+++ b/test/stdvector.cpp
@@ -17,7 +17,7 @@
   Index rows = m.rows();
   Index cols = m.cols();
   MatrixType x = MatrixType::Random(rows,cols), y = MatrixType::Random(rows,cols);
-  std::vector<MatrixType,Eigen::aligned_allocator<MatrixType> > v(10, MatrixType(rows,cols)), w(20, y);
+  std::vector<MatrixType,Eigen::aligned_allocator<MatrixType> > v(10, MatrixType::Zero(rows,cols)), w(20, y);
   v[5] = x;
   w[6] = v[5];
   VERIFY_IS_APPROX(w[6], v[5]);
@@ -86,8 +86,8 @@
 void check_stdvector_quaternion(const QuaternionType&)
 {
   typedef typename QuaternionType::Coefficients Coefficients;
-  QuaternionType x(Coefficients::Random()), y(Coefficients::Random());
-  std::vector<QuaternionType,Eigen::aligned_allocator<QuaternionType> > v(10), w(20, y);
+  QuaternionType x(Coefficients::Random()), y(Coefficients::Random()), qi=QuaternionType::Identity();
+  std::vector<QuaternionType,Eigen::aligned_allocator<QuaternionType> > v(10,qi), w(20, y);
   v[5] = x;
   w[6] = v[5];
   VERIFY_IS_APPROX(w[6], v[5]);