Use #ifndef for SASL_VERSION_FULL, new Cyrus <sasl.h> defines it now

contrib/ldapsasl/ldapdb.c

@@ -19,8 +19,10 @@
 #include "saslutil.h"
 #include "saslplug.h"
 
+#ifndef SASL_VERSION_FULL
 #define SASL_VERSION_FULL ((SASL_VERSION_MAJOR << 16) |\
 	(SASL_VERSION_MINOR << 8) |SASL_VERSION_STEP)
+#endif
 
 #include "plugin_common.h"