Fixes a couple of bugs with the Allman brace breaking.

In particular, left braces after an enum declaration now occur on their
own line.  Further, when short ifs/whiles are allowed these no longer
cause the left brace to be on the same line as the if/while when a
brace is included.

Patch by Thomas Gibson-Robinson.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@187901 91177308-0d34-0410-b5e6-96231b3b80d8