Changed the tests to be a little more robust on various compilers.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403693

dlib/test/svm.cpp

@@ -336,11 +336,11 @@ namespace
         typedef radial_basis_kernel<sample_type> kernel_type;
 
         rbf_network_trainer<kernel_type> rbf_trainer;
-        rbf_trainer.set_kernel(kernel_type(0.5*gamma));
+        rbf_trainer.set_kernel(kernel_type(gamma));
         rbf_trainer.set_num_centers(100);
 
         rvm_trainer<kernel_type> rvm_trainer;
-        rvm_trainer.set_kernel(kernel_type(2*gamma));
+        rvm_trainer.set_kernel(kernel_type(gamma));
 
         svm_pegasos<kernel_type> pegasos_trainer;
         pegasos_trainer.set_kernel(kernel_type(gamma));