MOSCOW (Reuters) - Russian oil major Rosneft has received court summons for its Chief Executive Igor Sechin to appear in court during the trial of ex-economy minister Alexei Ulyukayev, the judge read a letter from Sechin s lawyer on Wednesday. Sechin was called to court to testify but has missed the first two court sittings since then. In a letter to the court, his lawyer said Sechin s schedule would become tighter by the end of this year. Ulyukayev is on trial on charges of extorting a $2 million bribe from Sechin, in exchange for Ulyukayev s approval of a business deal. Ulyukayev denies the charges.         