Update NEWS.txt

NEWS.txt

@@ -8,6 +8,9 @@ Since 0.5rc2
  * 'theano-cache list' lists key files bigger than 1M
  * 'theano-cache list' prints an histogram of the number of keys per compiled module
  * 'theano-cache list' prints the number of compiled modules per op class
+ * Fix a bug with Gemv and Ger on CPU, when used on vectors with negative
+   strides. Data was read from incorrect (and possibly uninitialized)
+   memory space. This bug was probably introduced in 0.5rc1.
 
 =============
 Release Notes