handle transaction inputs correctly (#512)

* commit

* bump grin crates to latest version on master

libwallet/src/api_impl/foreign.rs

@@ -17,7 +17,6 @@ use strum::IntoEnumIterator;
 
 use crate::api_impl::owner::finalize_tx as owner_finalize;
 use crate::api_impl::owner::{check_ttl, post_tx};
-use crate::grin_core::core::transaction::Transaction;
 use crate::grin_keychain::Keychain;
 use crate::grin_util::secp::key::SecretKey;
 use crate::internal::{selection, tx, updater};
@@ -91,7 +90,7 @@ where
 		}
 	}
 
-	ret_slate.tx = Some(Transaction::empty());
+	ret_slate.tx = Some(Slate::empty_transaction());
 
 	let height = w.last_confirmed_height()?;
 	let keychain = w.keychain(keychain_mask)?;

libwallet/src/api_impl/owner.rs

@@ -647,7 +647,7 @@ where
 	}
 
 	// if this is compact mode, we need to create the transaction now
-	ret_slate.tx = Some(Transaction::empty());
+	ret_slate.tx = Some(Slate::empty_transaction());
 
 	// if self sending, make sure to store 'initiator' keys
 	let context_res = w.get_private_context(keychain_mask, slate.id.as_bytes());
@@ -721,7 +721,7 @@ where
 	let mut sl = slate.clone();
 
 	if sl.tx == None {
-		sl.tx = Some(Transaction::empty());
+		sl.tx = Some(Slate::empty_transaction());
 		selection::repopulate_tx(&mut *w, keychain_mask, &mut sl, &context, true)?;
 	}