replace assert.h with cassert

The former was deprecated with C++14.

According to the C++11 and C++17 standards, both files are identical.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/db/update/Editor.cxx

@@ -24,7 +24,7 @@
 #include "db/plugins/simple/Directory.hxx"
 #include "db/plugins/simple/Song.hxx"
 
-#include <assert.h>
+#include <cassert>
 
 void
 DatabaseEditor::DeleteSong(Directory &dir, Song *del)

src/db/update/ExcludeList.cxx

@@ -29,7 +29,7 @@
 #include "util/StringStrip.hxx"
 #include "config.h"
 
-#include <assert.h>
+#include <cassert>
 
 #ifdef HAVE_CLASS_GLOB
 

src/db/update/InotifyUpdate.cxx

@@ -27,11 +27,11 @@
 #include "fs/Traits.hxx"
 #include "Log.hxx"
 
-#include <string>
-#include <map>
+#include <cassert>
 #include <forward_list>
+#include <map>
+#include <string>
 
-#include <assert.h>
 #include <sys/inotify.h>
 #include <string.h>
 #include <dirent.h>

src/db/update/Service.cxx

@@ -36,7 +36,7 @@
 #include "event/Loop.hxx"
 #endif
 
-#include <assert.h>
+#include <cassert>
 
 UpdateService::UpdateService(const ConfigData &_config,
 			     EventLoop &_loop, SimpleDatabase &_db,

src/db/update/Walk.cxx

@@ -38,10 +38,10 @@
 #include "util/UriExtract.hxx"
 #include "Log.hxx"
 
+#include <cassert>
 #include <exception>
 #include <memory>
 
-#include <assert.h>
 #include <string.h>
 #include <stdlib.h>
 #include <errno.h>