MIDEAST STOCKS-State budget boosts Saudi, rest of Gulf sluggish; Egypt drops

* Analysts think overall Saudi growth will slow in 2017 * But investors focus on positives; trading volume rises * Saudi Electricity surges on expected power price hike * Delay of gas feedstock price hike buoys petrochemicals * Mobily down, Abu Dhabi's Etisalat up; management tie expires By Andrew Torchia DUBAI, Dec 25 (Reuters) - Saudi Arabia's stock market rose sharply on Sunday in response to the release of the 2017 state budget, which includes an increase in government spending, while other