Israeli warplanes Thursday rocketed bases of Palestinian terrorist Abu Nidal outside the southern Lebanese port of Sidon for the second time in 13 hours, and police reported an undetermined number of casualties. Two Israeli jets roared in at 10:05 a.m. to attack camps belonging to Abu Nidal's Fatah-Revolutionary Council in Majdalyoun Valley, four miles east of Sidon. Israeli military authorities said the bases served as a planning and staging areas for terrorist attacks.