Fix for issue 127

[mudinthewater]

Fixes https://github.com/regebro/tzlocal/issues/127 by adding a break to the while-loop that checks for valid paths from a simlink from /etc/localtime. The behavior of the loop is to check for valid files from the top down like this:

Example behavior with latest release and /etc/localtime -> /usr/share/zoneinfo/Etc/UTC

/usr/share/zoneinfo/Etc/UTC usr/share/zoneinfo/Etc/UTC share/zoneinfo/Etc/UTC zoneinfo/Etc/UTC Etc/UTC UTC

Creates an invalid configuration ('Etc/UTC' and 'UTC' don't match) because both '/usr/share/zoneinfo/Etc/UTC' and '/usr/share/zoneinfo/UTC' exist and are valid configurations:

{'/etc/sysconfig/clock': 'Etc/UTC', '/etc/localtime is a symlink to': 'UTC'}

With the while loop breaking on the first valid configuration, the desired behavior is realized:

/usr/share/zoneinfo/Etc/UTC usr/share/zoneinfo/Etc/UTC share/zoneinfo/Etc/UTC zoneinfo/Etc/UTC Etc/UTC {'/etc/sysconfig/clock': 'Etc/UTC', '/etc/localtime is a symlink to': 'Etc/UTC'}

Adding the break does not affect the opposite scenario, where the simlink points to /usr/share/zoneinfo/UTC, as the first valid config will still be 'UTC'.

tests pass:

coverage: platform linux, python 3.8.10-final-0 Name Stmts Miss Cover

tzlocal/init.py 4 0 100% tzlocal/unix.py 116 0 100% tzlocal/utils.py 57 1 98% tzlocal/win32.py 69 1 99% tzlocal/windows_tz.py 3 0 100%

TOTAL 249 2 99%