Fix linked_list::remove_if()

When remove_if removes last element from the list
following push_back stops working.

Change-Id: Ia3e92763b83a2e172eaa10de7aecfb7a4be452d7
diff --git a/linker/linked_list.h b/linker/linked_list.h
index 8003dbf..eb3ecd4 100644
--- a/linker/linked_list.h
+++ b/linker/linked_list.h
@@ -127,6 +127,11 @@
         } else {
           p->next = next;
         }
+
+        if (tail_ == e) {
+          tail_ = p;
+        }
+
         Allocator::free(e);
         e = next;
       } else {
diff --git a/linker/tests/linked_list_test.cpp b/linker/tests/linked_list_test.cpp
index 09ad687..12348d9 100644
--- a/linker/tests/linked_list_test.cpp
+++ b/linker/tests/linked_list_test.cpp
@@ -133,6 +133,23 @@
   ASSERT_TRUE(list.pop_front() == nullptr);
 }
 
+TEST(linked_list, remove_if_last_then_push_back) {
+  test_list_t list;
+
+  list.push_back("a");
+  list.push_back("b");
+  list.push_back("c");
+  list.push_back("d");
+
+  list.remove_if([](const char* c) {
+    return *c == 'c' || *c == 'd';
+  });
+
+  ASSERT_EQ("ab", test_list_to_string(list));
+  list.push_back("d");
+  ASSERT_EQ("abd", test_list_to_string(list));
+}
+
 TEST(linked_list, copy_to_array) {
   test_list_t list;
   const size_t max_size = 128;