Mark SRP_VBASE_get_by_user() as deprecated

The function SRP_VBASE_get_by_user() is declared as deprecated but the
implementation was not.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/crypto/srp/srp_vfy.c b/crypto/srp/srp_vfy.c
index 0d3da7e..78db608 100644
--- a/crypto/srp/srp_vfy.c
+++ b/crypto/srp/srp_vfy.c
@@ -502,6 +502,7 @@
     return NULL;
 }
 
+ #if OPENSSL_API_COMPAT < 0x10100000L
 /*
  * DEPRECATED: use SRP_VBASE_get1_by_user instead.
  * This method ignores the configured seed and fails for an unknown user.
@@ -512,6 +513,7 @@
 {
     return find_user(vb, username);
 }
+#endif
 
 /*
  * Ownership of the returned pointer is released to the caller.