Politico: The Obama administration will approve a boost in gasoline’s ethanol content for new cars on Wednesday, in a partial victory for supporters of the corn-based fuel. The Environmental Protection Agency is expected to issue its long-awaited decision on a petition from the ethanol industry, which wants to raise the amount of ethanol allowed in gasoline to 15 percent from the current 10 percent. EPA will approve the use of gasoline with 15 percent ethanol (E15) for new vehicles built …