Revert "Fix critical lens distortion bug in libmv after rB3a7d62cd1f5e."

This reverts commit 7e836bde11.

Reverting the incomplete workaround, due to the following reasoning:

- There should be no dependency between CameraIntrinsics and the bundler
  code. This violates intended abstraction of the intrinsics class.

- The fix was not complete, or wrong. Even in the world where there is
  a requirement to the parameters storage size this should have applied
  to all distortion models, including Divisions, Nuke.

Proper fix will be committed next.

intern/libmv/libmv/simple_pipeline/bundle.cc

@@ -47,10 +47,6 @@ enum {
   OFFSET_PRINCIPAL_POINT_Y,
 
   // Distortion model coefficients.
-  // WARNING: camera intrinsics are not required to define/use all of those,
-  // but they have to define all of them up to the last one they need, in that
-  // exact same order. See e.g. how `PolynomialCameraIntrinsics` needs to define
-  // `OFFSET_K4`, even though it does not use it.
   OFFSET_K1,
   OFFSET_K2,
   OFFSET_K3,

intern/libmv/libmv/simple_pipeline/camera_intrinsics.h

@@ -281,7 +281,6 @@ class PolynomialCameraIntrinsics : public CameraIntrinsics {
     OFFSET_K1,
     OFFSET_K2,
     OFFSET_K3,
-    OFFSET_K4,  // Unused, needed to map properly with all deform parameters defined in bundle.cc.
     OFFSET_P1,
     OFFSET_P2,