clang-format: Adjust short functions / if settings.

http://clang.llvm.org/docs/ClangFormatStyleOptions.html

AllowShortFunctionsOnASingleLine: Empty
  Empty functions like "int f() {}" can be put on a single line.

AllowShortIfStatementsOnASingleLine: true
  If true, "if (a) return;" can be put on a single line.

Test: N/A
Change-Id: Ia4f411a958235ab18d16972f2c9d0f55b645b4ba