Make SecBlock<T,A> data members protected

Also see http://github.com/weidai11/cryptopp/issues/448

secblock.h

@@ -796,7 +796,7 @@ public:
 		std::swap(m_ptr, b.m_ptr);
 	}
 
-// protected:
+protected:
 	A m_alloc;
 	size_type m_mark, m_size;
 	T *m_ptr;

sosemanuk.cpp

@@ -601,9 +601,9 @@ void SosemanukPolicy::OperateKeystream(KeystreamOperation operation, byte *outpu
 		AS_POP_IF86(	bx)
 		ATT_PREFIX
 			:
-			: "a" (m_state.m_ptr), "c" (iterationCount), "S" (s_sosemanukMulTables), "D" (output), "d" (input)
+			: "a" (m_state.data()), "c" (iterationCount), "S" (s_sosemanukMulTables), "D" (output), "d" (input)
 	#if CRYPTOPP_BOOL_X64
-			, "r" (workspace.m_ptr)
+			, "r" (workspace.data())
 			: "memory", "cc", "%r9", "%r10", "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", "%xmm6", "%xmm7"
 	#else
 			: "memory", "cc"