SSH-AGENT Update

1. Remove redundant include from agent.h.
2. Add global disable flags for SSH-RSA using SHA2-256 and SHA2-512.
   These are possible signatures indications when using the ssh-agent.

Author: ejohnstown

wolfssh/agent.h

@@ -35,7 +35,6 @@
 #include <wolfssl/wolfcrypt/dh.h>
 #include <wolfssl/wolfcrypt/ecc.h>
 #include <wolfssl/wolfcrypt/rsa.h>
-#include <wolfssl/wolfcrypt/sha256.h>
 
 
 #ifdef __cplusplus

wolfssh/internal.h

@@ -160,6 +160,15 @@ extern "C" {
     #undef WOLFSSH_NO_SSH_RSA_SHA1
     #define WOLFSSH_NO_SSH_RSA_SHA1
 #endif
+#if defined(WOLFSSH_NO_RSA) || defined(NO_SHA256)
+    #undef WOLFSSH_NO_SSH_RSA_SHA2_256
+    #define WOLFSSH_NO_SSH_RSA_SHA2_256
+#endif
+#if defined(WOLFSSH_NO_RSA) || !defined(WOLFSSL_SHA512)
+    #undef WOLFSSH_NO_SSH_RSA_SHA2_512
+    #define WOLFSSH_NO_SSH_RSA_SHA2_512
+#endif
+
 #if defined(WOLFSSH_NO_ECDSA) || \
     defined(NO_SHA256) || defined(NO_ECC256)
     #undef WOLFSSH_NO_ECDSA_SHA2_NISTP256