JOHANNESBURG—A South African court has ordered that former President Jacob Zuma should go back to prison after withdrawing the medical parole given to him earlier this year. Zuma was released from prison in September after serving about two months of his 15-month sentence for defying a Constitutional Court order that he should testify before a state commission investigating allegations of corruption when he was president from 2009 to 2018. On Wednesday the Gauteng High Court in Pretoria ruled that the medical parole granted to Zuma was illegal as it went against the recommendation of the medical parole board. The court ruled that Zuma should go back to prison. According to the ruling, the time that Zuma spent outside prison should not be counted as part of the sentence imposed by the court. The ruling is a legal blow for Zuma, who is also facing corruption charges for allegedly receiving bribes …