Fixed compile time warning.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402659

dlib/matrix/matrix_utilities.h

@@ -851,7 +851,7 @@ namespace dlib
 
         const long m = a.nr();
         const long n = a.nc();
-        long i, j, k, l, l1, iter, retval;
+        long i, j, k, l = 0, l1, iter, retval;
         T c, f, g, h, s, x, y, z;
 
         matrix<T,qN,1,MM2> e(n,1);