Changed test to make it a little more robust.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403479

dlib/test/optimization.cpp

@@ -693,7 +693,7 @@ namespace
         const double p
     )
     {
-        const double eps = 1e-9;
+        const double eps = 1e-7;
 
 
         dlog << LINFO << "testing with single_variable_function and the start point: " << p;