b=19336 post landing cleanups

b=19336 post landing cleanups

Remove generic find_linux_devel_paths()
- now that both the rhel5 and sles method files have their own particular
  version of this method, remove this hacky-trying-to-work-for-both versions
  from lbuild.
Remove a block of what is now redundant code.
Remove the comments from the target files describing what happened with
this bug.
Align the sles10 and sles11 target files:
- include the rpmfix specifier in the sles10 file
- remove the EXTRA_VERSION_DELIMETER from the sles10 file
- change the TARGET_DELIMETER to FLAVOR_DELIMETER in the sles11 file
Some whitespace cleanups.

i=wangyb
i=yangsheng