use lowercase for variables

The convention for good shell coding style is uppercase for constants,
lowercase for normal variables.
refactor plog_files and pconf_files

Avoid duplicated code, and add support for capture filters.
Ideally this would be moved back upstream into
/usr/lib/supportconfig/resources/scplugin.rc
censor passwords when collecting Chef data bag *.json files (bnc#808887)
Merge pull request #7 from aspiers/suse-cloud-2.0

censor passwords when collecting Chef data bag *.json files (bnc#808887)