hashtable: fix possible bad pointer dereference

src/include/hashtable/hashtable.c

@@ -58,10 +58,10 @@ bool hashtable_insert(hashtable* table, char* key, void* val){
 
 	char* keysave = alloc(strlen(key)+1);
 
-	memcpy(keysave, key, strlen(key)+1);
-
 	if(!keysave) return false;
 
+	memcpy(keysave, key, strlen(key)+1);
+
 	if(entry->key){
 		while(entry->next)
 			entry = entry->next;