Don't leak rasterizer discard state if GL postvs fails

renderdoc/driver/gl/gl_postvs.cpp

@@ -215,9 +215,6 @@ void GLReplay::InitPostVSBuffers(uint32_t eventId)
   list<string> matrixVaryings;    // matrices need some fixup
   vector<const char *> varyings;
 
-  // we don't want to do any work, so just discard before rasterizing
-  drv.glEnable(eGL_RASTERIZER_DISCARD);
-
   CopyProgramAttribBindings(stageSrcPrograms[0], vsProg, vsRefl);
 
   varyings.clear();
@@ -402,6 +399,9 @@ void GLReplay::InitPostVSBuffers(uint32_t eventId)
   // the vertex stage
   CopyProgramUniforms(stageSrcPrograms[0], vsProg);
 
+  // we don't want to do any work, so just discard before rasterizing
+  drv.glEnable(eGL_RASTERIZER_DISCARD);
+
   // bind our program and do the feedback draw
   drv.glUseProgram(vsProg);
   drv.glBindProgramPipeline(0);