Please read the narration in Muslim referred to Abu Dhar (ra).
The above narration says that Mutta al-Hajj was only specified for the companions of the Holy Prophet. This narration contradicts with the Quranic Verse 2:196
"...then whosoever (do Mutta of hajj) enjoys the Visitation until the Pilgrimage, let his offering be such as may be feasible...".
In this verse Mutta of Hajj is mentioned arabic words.
2nd point:
The narration of Abu Dhar(ra) contradicts with the narration of Imran bin Hossin (ra). Please find that narration here.
http://www.shiasunni.info/shocking-facts-about-sahih-muslim/umar-bin-khattab-in-sahih-muslim/308-companions-of-the-prophet-were-scared-from-umar-bin-khattab
3rd point:
The narration referred to Abu Dhar (ra) contradicts with the narration of Ibne Abbas (ra).
In the above narration Ibne Abbas(ra) said that Mutta of Hajj is allowed until the day of Judgment (not only specific for the companions of the Prophet(pbuh) ) this is also Sunnah of the Holy Prophet(pbuh) because the Prophet(pbuh) ordered to do Mutta al-Hajj.