Remove unused BORINGSSL_PREFIX.

Change-Id: Ifd7239106471bb59057b0a65c6e91837379c78bf
Reviewed-on: https://boringssl-review.googlesource.com/31164
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

include/openssl/base.h

diff --git a/include/openssl/base.h b/include/openssl/base.h
index dc30651..aa1be1f 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -71,10 +71,6 @@
 #include <openssl/is_boringssl.h>
 #include <openssl/opensslconf.h>
 
-#if defined(BORINGSSL_PREFIX)
-#include <boringssl_prefix_symbols.h>
-#endif
-
 #if defined(__cplusplus)
 extern "C" {
 #endif