refactorize: map_string_t clean up

libreport hides GHashTable behind map_string_t and adds some utility
functions using map_string_t type. Programmer should use map_string_t
instead of GHashTable but libreport calls some GHashTable functions
directly. This patch adds wrappers for GHashTable functions and makes
libreport using them.

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
dd: add /etc/os-release to basic files

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
add function for parsing os-release

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
unit tests: add test for osinfo parsers

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
problem data: add function getting parsed osinfo

The function loads os_info from chrooted directory if problem data
contains chrootdir item, otherwise loads the standard os_info.

If os_info item is not pressent, the function adds PRETTY_NAME
key with content of os_release item to the result map.

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
unit tests: add test for problem data get osinfo

Related to #147

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
plugins: support /etc/os-release

Related to #147 (os-release)

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>