Use compare-type REG_EXP for Python job file paths

Change compare-type to REG_EXP in macros lf_python_clm_xc and
lf_pypi_common for config parameter gerrit_trigger_file_paths
with the regular expression .*
Previously was ANT, which didn't match anything with pattern .*
so recheck/reverify comment triggers did not work.
Clarify documentation of comment triggers for python jobs.

Change-Id: Id926d83e454fce2aa795b15d27c794fc41bbd1d3
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>