intel: Change vendor string to "Intel Open Source Technology Center".

Tungsten Graphics has not existed for several years, and the majority of
ongoing development and support is done by Intel.  I chose to include
"Open Source Technology Center" to distinguish it from, say, the closed
source Windows OpenGL driver.

The one downside to this patch is that applications that pattern match
against "Intel" may start applying workarounds meant for the Windows
driver.  However, it does seem like the right thing to do.

This does change oglconform behavior.

Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Acked-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/intel/intel_context.c

@@ -72,7 +72,7 @@ intelGetString(struct gl_context * ctx, GLenum name)
 
    switch (name) {
    case GL_VENDOR:
-      return (GLubyte *) "Tungsten Graphics, Inc";
+      return (GLubyte *) "Intel Open Source Technology Center";
       break;
 
    case GL_RENDERER: