fix for calling bindFragDataLocation on OpenGL 2.1

BUG=skia:3966

Review URL: https://codereview.chromium.org/1201623003
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index c7dc862..b23619d 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -47,6 +47,7 @@
     fUseNonVBOVertexAndIndexDynamicData = false;
     fIsCoreProfile = false;
     fFullClearIsFree = false;
+    fBindFragDataLocationSupport = false;
 
     fReadPixelsSupportedCache.reset();
 
@@ -270,6 +271,10 @@
         fMultisampleDisableSupport = false;
     }
 
+    if (kGL_GrGLStandard == standard && version >= GR_GL_VER(3, 0)) {
+        fBindFragDataLocationSupport = true;
+    }
+
     /**************************************************************************
     * GrShaderCaps fields
     **************************************************************************/