Core/Spells: Yet another spell typo fix from previous commit
http://www.wowwiki.com/Glyph_of_Regrowth
@ 50% hp is not for 406a this is current MoP value.

correct patch changeset:
Patch 4.0.6 (8-Feb-2011): Changed from Your Regrowth heal-over-time will automatically refresh its duration on targets at or below 25% health.

Signed-off-by: bootz <bootz@projectskyfire.org>