Fixed program names in help output.

tests/gamma.c

@@ -41,7 +41,7 @@ static GLfloat gamma = 1.0f;
 
 static void usage(void)
 {
-    printf("Usage: gammatest [-h] [-f]\n");
+    printf("Usage: gamma [-h] [-f]\n");
 }
 
 static void set_gamma(float value)

tests/glfwinfo.c

@@ -51,7 +51,7 @@
 
 static void usage(void)
 {
-    printf("Usage: version [-h] [-m MAJOR] [-n MINOR] [-d] [-l] [-f] [-p PROFILE] [-r STRATEGY]\n");
+    printf("Usage: glfwinfo [-h] [-m MAJOR] [-n MINOR] [-d] [-l] [-f] [-p PROFILE] [-r STRATEGY]\n");
     printf("available profiles: " PROFILE_NAME_CORE " " PROFILE_NAME_COMPAT " " PROFILE_NAME_ES2 "\n");
     printf("available strategies: " STRATEGY_NAME_NONE " " STRATEGY_NAME_LOSE "\n");
 }