Fix glancing blows formula for classic

In classic a difference in skill points should reward an extra 2% chance
of
getting a glancing blow.

source: http://www.wowwiki.com/Glancing_blow#Glancing_Blow_chance
Merge pull request #29 from cala/glancingblows

Fix glancing blows formula for classic
[z2351] Sync mangos.sql file with master

(based on commit [s1997] - 0ad36e3)
Merge pull request #2 from cmangos/master