Remove spurious ;

DECLARE_STACK_OF adds a trailing ; so we don't need a second one added
here.

Compiling a project using boringssl which uses -Werror,-Wextra-semi I
get errors:

```
third_party/boringssl/include/openssl/stack.h:374:1: error: extra ';' outside of a function [-Werror,-Wextra-semi]
DEFINE_STACK_OF(void)
^
third_party/boringssl/include/openssl/stack.h:355:3: note: expanded from macro 'DEFINE_STACK_OF'
  BORINGSSL_DEFINE_STACK_OF_IMPL(type, type *, const type *) \
  ^
third_party/boringssl/include/openssl/stack.h:248:25: note: expanded from macro 'BORINGSSL_DEFINE_STACK_OF_IMPL'
  DECLARE_STACK_OF(name);                                                      \
                        ^
third_party/boringssl/include/openssl/stack.h:375:1: error: extra ';' outside of a function [-Werror,-Wextra-semi]
DEFINE_SPECIAL_STACK_OF(OPENSSL_STRING)
^
third_party/boringssl/include/openssl/stack.h:369:3: note: expanded from macro 'DEFINE_SPECIAL_STACK_OF'
  BORINGSSL_DEFINE_STACK_OF_IMPL(type, type, const type)
  ^
third_party/boringssl/include/openssl/stack.h:248:25: note: expanded from macro 'BORINGSSL_DEFINE_STACK_OF_IMPL'
  DECLARE_STACK_OF(name);                                                      \
                        ^
2 errors generated.
```

Change-Id: Icc39e2341eb76544be72d2d7d0bd29e2f1ed0bf9
Reviewed-on: https://boringssl-review.googlesource.com/23404
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/stack.h b/include/openssl/stack.h
index 1a0347e..46f57a3 100644
--- a/include/openssl/stack.h
+++ b/include/openssl/stack.h
@@ -245,7 +245,7 @@
 // are defined in a header.
 
 #define BORINGSSL_DEFINE_STACK_OF_IMPL(name, ptrtype, constptrtype)            \
-  DECLARE_STACK_OF(name);                                                      \
+  DECLARE_STACK_OF(name)                                                       \
                                                                                \
   typedef int (*stack_##name##_cmp_func)(constptrtype *a, constptrtype *b);    \
                                                                                \