Linux v2.6.15-rc1

As per the new release rules: two weeks of merging, and then an -rc1 and
calming down for the next release.

Makefile

 VERSION = 2
 PATCHLEVEL = 6
-SUBLEVEL = 14
-EXTRAVERSION =
+SUBLEVEL = 15
+EXTRAVERSION =-rc1
 NAME=Affluent Albatross
 
 # *DOCUMENTATION*