Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says that the Prophet (peace and blessings be upon him) was asked about a person who shaved his head before sacrificing, and something similar was asked, and he (peace and blessings be upon him) said: "There is no harm, there is no harm."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9627