Revert "QDirIterator: clarify the docs wrt. calling hasNext() before next()"

This reverts commit c83304af27b403c9ebe64d4c768da25e04acafc1.

The original behavior is going to be finally restored by the next
commits in this chain.

Task-number: QTBUG-135287
Change-Id: Iae38d5d9271a77da9d9b1c938ccc73c7531d89d5
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qdiriterator.cpp

@@ -208,8 +208,8 @@ QDirIterator::~QDirIterator()
 
 /*!
     Advances the iterator to the next entry, and returns the file path of this
-    new entry. You should first check hasNext() before using this method, to
-    avoid unexpected results.
+    new entry. If hasNext() returns \c false, this function does nothing, and
+    returns an empty QString.
 
     You can call fileName() or filePath() to get the current entry's file name
     or path, or fileInfo() to get a QFileInfo for the current entry.
@@ -228,8 +228,8 @@ QString QDirIterator::next()
     \since 6.3
 
     Advances the iterator to the next entry, and returns the file info of this
-    new entry. You should first check hasNext() before using this method, to
-    avoid unexpected results.
+    new entry. If hasNext() returns \c false, this function does nothing, and
+    returns an empty QFileInfo.
 
     You can call fileName() or filePath() to get the current entry's file name
     or path, or fileInfo() to get a QFileInfo for the current entry.