Nigeria's oil minister has finally approved Shell Plc’s (NYSE:SHEL) sale of $2.4 billion in assets to Renaissance Group, Renaissance has revealed. The greenlight comes just two months after Africa's biggest crude producer declined to approve the sale of Shell's onshore and shallow-water oil and gas in the Niger Delta region to a consortium of local companies. The rejection marked a setback for Shell, which has sought to exit the West African oil sector that’s currently plagued by significant oil spills and theft. The Nigerian assets…