Grading: This chain is "very weak" because of "Abu Muslim, the guide of al-A'mash" (whose name is 'Ubayd Allah bin Sa'id bin Muslim).
Technical note / Defect ('illah): Imam al-Bukhari said: "Fi hadithihi nazar." Al-'Uqayli said in "al-Du'afa'" (3/ 618): He makes many errors in narrating from al-A'mash. Ibn Hibban said in "al-Majruhin" (1/ 239): He narrates alone, from al-A'mash and other narrators, things in which he is not corroborated. Abu Dawud stated with certainty that he had fabricated (mawdu') hadiths.

Note / Clarification: This report is also narrated from Abu Hurayrah (may Allah be pleased with him) by another chain, but it too is "not reliable".

Reference / Source: Al-Tabarani narrated it in "al-Kabir" (2629) and "al-Saghir" (1122), al-Khatib in "Tarikh Baghdad" (4/ 236) and "Talkhis al-Mutashabih" (1/ 381), Ibn 'Asakir (10/ 458) and Ibn al-Jawzi in "al-Mawdu'at" (1795) via "'Abd Allah bin Salih, the scribe of al-Layth".
Technical note / Defect ('illah): But this narration does not mention Fatimah al-Zahra'; rather, in her place her two sons al-Hasan and al-Husayn (may Allah be pleased with them both) are mentioned, that they will be resurrected on she-camels. Its chain is "very weak". In this route 'Abd Allah bin Salih is alone, and he has "poor memory" (sayyi' al-hifz). Moreover Ibn Jurayj is a "mudallis" and has used 'an'anah, and apart from this report no direct narration of Ibn Jurayj from Muhammad bin Ka'b al-Qurazi is known; otherwise he generally narrates from him through one or two intermediaries.

Reference / Source: Similar narrations are also reported from Companions other than Abu Hurayrah, but their chains contain "accused" (accused of lying) and "unknown" (majhul) narrators. For details see: Ibn al-Jawzi's "al-Mawdu'at" (3/ 564-565), al-Suyuti's "al-La'ali' al-Masnu'ah" (1/ 342-344) and al-Albani's "Silsilat al-Ahadith al-Da'ifah" (771-773 and 6130).