Expand range of ctrls for AES GCM to support retrieval and setting of
invocation field.

Add complete support for AES GCM ciphersuites including all those in
RFC5288 and RFC5289.

ssl/ssl.h

diff --git a/ssl/ssl.h b/ssl/ssl.h
index 244cfb2..871327d 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h
@@ -287,6 +287,7 @@
 #define SSL_TXT_AES128		"AES128"
 #define SSL_TXT_AES256		"AES256"
 #define SSL_TXT_AES		"AES"
+#define SSL_TXT_AES_GCM		"AESGCM"
 #define SSL_TXT_CAMELLIA128	"CAMELLIA128"
 #define SSL_TXT_CAMELLIA256	"CAMELLIA256"
 #define SSL_TXT_CAMELLIA	"CAMELLIA"