switch to clang-format-3.8 (#2547)

https://llvm.org/bugs/show_bug.cgi?id=30353 was filed for the unintended
line break between in e.g. “TAILQ_ENTRY(foo)\nbar;”.

Until that’s fixed or a workaround is known, we’ll live with line
breaks. To make it a bit easier for readers to see what’s going on, I
added extra line breaks around each such struct member/variable
definition, so that they at least visually are a single unit.

fixes #2174

src/config_parser.c

@@ -1002,7 +1002,7 @@ bool parse_file(const char *f, bool use_nagbar) {
         char *next;
         for (next = bufcopy;
              next < (bufcopy + stbuf.st_size) &&
-                 (next = strcasestr(next, current->key)) != NULL;
+             (next = strcasestr(next, current->key)) != NULL;
              next += strlen(current->key)) {
             *next = '_';
             extra_bytes += extra;