[compiz] blur plugin and GL_ARB_fragment_program extension

[Ioannis Nousias]

The blur plugin has GL_ARB_fragment_program extension as a prerequisite. 
At least that's what I'm getting by looking at screen.c.

I think there should be a check for the "CompScreen::fragmentProgram" 
flag somewhere in blur.c to prevent it from loading or at least 
executing a <null> pointer.

I get a crash in line blur.c:1858, because 
CompScreen::programEnvParameter4f is zero.

I have a NV28 with 1.0-9631 binary drivers and a rv250 with Xorg7.1 
drivers, none of which have the above extension.

thanks


PS: compiz from today's git version