Change code that goes through the directory structure so that it
no longer reads entire directory cataloges into memory at once.
This should reduce the memory usage of file_space_account when
encountering direcories whith a large amount of files.

Fix on handling of multiple matches with globbing in
/var/opt/openit/etc/file_space config. Previously selection of the
desired account would often fail, giving a wrong account in the data.

The STORAGE_AUTOEXCLUDE_LEVEL now defines the first level as the
directory below the top-level directory, e.g. "/*". Earlier the
top-level directory itself, e.g. "/" was defined as the first level,
causing some confusion. The default is two levels from root-dir,
i.e. directories matching "/*" or "/*/*" will be checked for
automounted directories with file_space config file empty and
STORAGE_AUTOEXCLUDE_LEVEL undefined.

"snapshot" directories are now removed by default.

Handling of full disk on the collector host is improved.

The STORAGE_AUTOEXCLUDE_LEVEL now defines the first level as the
directory below the top-level directory, e.g. "/*". Earlier the
top-level directory itself, e.g. "/" was defined as the first level,
causing some confusion. The default is two levels from root-dir,
i.e. directories matching "/*" or "/*/*" will be checked for
automounted directories with file_space config file empty and
STORAGE_AUTOEXCLUDE_LEVEL undefined.

5.1, 5.1.0.1: shapshot directories are now removed by
default. Handling of full disk on the collector host is improved.

The STORAGE_AUTOEXCLUDE_LEVEL now defines the first level as the
directory below the top-level directory, e.g. "/*". Earlier the
top-level directory itself, e.g. "/" was defined as the first level,
causing some confusion. The default is two levels from root-dir,
i.e. directories matching "/*" or "/*/*" will be checked for
automounted directories with file_space config file empty and
STORAGE_AUTOEXCLUDE_LEVEL undefined.

5.0, 5.0.1: shapshot directories are now removed by default. Handling
of full disk on the collector host is improved.

Accounting of files sometimes needs use of df and ls. This should now
work also when there are spaces in file/path name.

Accounting of files sometimes needs use of df and ls. This should now
work also when there are spaces in file/path name.