Fixed memory leak if BUF_MEM_grow fails

Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

ssl/d1_srvr.c

@@ -251,6 +251,7 @@ int dtls1_accept(SSL *s)
 					}
 				if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
 					{
+					BUF_MEM_free(buf);
 					ret= -1;
 					goto end;
 					}

ssl/s23_srvr.c

@@ -185,6 +185,7 @@ int ssl23_accept(SSL *s)
 					}
 				if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
 					{
+					BUF_MEM_free(buf);
 					ret= -1;
 					goto end;
 					}