[one] Re-add Deep Wounds code

[stfx]

What bug does the patch fix? What features does the patch add?

Re-add Deep Wounds code which was removed in the process of backporting the spell proc system in https://github.com/mangos-one/server/commit/5a793dad31ac7d858de030996c3afd444ef928c1

For which repository revision was the patch created?

s1333 (mangos-one)

Who has been writing this patch? Please include either forum user names or email addresses.

Me

http://pastebin.com/2MZSLWSK

Quote from commit msg: "Possible some early backported commits to mangos-0.12 including lost (not applied because related code not has been backported yet)"

Well I guess this was one of them as it was moved to Unit.cpp in https://github.com/mangos-one/server/commit/d8c22dc17d (even though there have been 5months between those)

[stfx]

Added in [s1419] with fixed percentage of damage. Thanks to Nighoo for testing it.