external/boringssl: fix |SSLeay|.

SSLeay is a compatibility function for OpenSSL, but I got it wrong.
It doesn't return a string, it returns a number. This doesn't end up
making any difference, but it fixes a warning when building OpenSSH.

Bug: 21304170
Change-Id: I3e4bb0240b18647cfe2a3ce5869948a4527ff0f0

src/crypto/crypto.c

@@ -104,9 +104,9 @@ void CRYPTO_library_init(void) {
 }
 
 const char *SSLeay_version(int unused) {
-  return SSLeay();
+  return "BoringSSL";
 }
 
-const char *SSLeay(void) {
-  return "BoringSSL";
+unsigned long SSLeay(void) {
+  return OPENSSL_VERSION_NUMBER;
 }

src/include/openssl/crypto.h

@@ -46,8 +46,9 @@ OPENSSL_EXPORT void CRYPTO_library_init(void);
  * "BoringSSL". */
 OPENSSL_EXPORT const char *SSLeay_version(int unused);
 
-/* SSLeay is a compatibility function that returns the string "BoringSSL". */
-OPENSSL_EXPORT const char *SSLeay(void);
+/* SSLeay is a compatibility function that returns OPENSSL_VERSION_NUMBER from
+ * base.h. */
+OPENSSL_EXPORT unsigned long SSLeay(void);
 
 
 #if defined(__cplusplus)