Description: Fix stack smashing crash in *gemmBatch

Calling ARRAY_INIT more than 3 times without resetting num_ev
runs off the end of evl.

Author: Rebecca N. Palmer <rebecca_palmer@zoho.com>
Forwarded: https://github.com/Theano/libgpuarray/pull/584

--- a/src/gpuarray_blas_opencl_clblas.c
+++ b/src/gpuarray_blas_opencl_clblas.c
@@ -136,6 +136,7 @@ static int sgemmBatch(cb_order order, cb
   cl_uint num_ev = 0;
 
   for (i = 0; i < batchCount; i++) {
+    num_ev = 0;
     ARRAY_INIT(A[i]);
     ARRAY_INIT(B[i]);
     ARRAY_INIT(C[i]);
@@ -167,6 +168,7 @@ static int dgemmBatch(cb_order order, cb
   cl_uint num_ev = 0;
 
   for (i = 0; i < batchCount; i++) {
+    num_ev = 0;
     ARRAY_INIT(A[i]);
     ARRAY_INIT(B[i]);
     ARRAY_INIT(C[i]);