[clang-rename] exit code-related bugfix and code cleanup

This patch does the following:

* enforces proper formatting for few files (i.e. deals with 80 linewidth violations and few other things)
* ensures '\n' chars are passed to the output streams instead of "\n" strings
* fixes a bug caused by calling cl::PrintHelpMessage(), which occasionally calls exit(0), so that exit(1) (which is right after cl::PrintHelpMessage line) becomes dead code

Patch by Kirill Bobyrev!

Differential Revision: http://reviews.llvm.org/D22091

llvm-svn: 275387