json-edit: Support editing arrays

When an element of the path is an integer and the parent attribute is an
array, then we just continue as expected, instead of changing the parent
attribute to a hash and overwriting things.
json-edit: Improve error reporting

We can provide the path to current attribute causing an error.
json-edit: Respect --no-clobber for parent attributes too

If a parent attribute exist, but the full path doesn't exist because the
parent attribute is not a hash or array, respect --no-clobber.
Relax SLES media check

When using the DEPS iso, SLES11-SP3-Pool is not needed.
adding SLE12 based repositories
Merge pull request #2067 from toabctl/skip-repos-for-deps-usage

Relax SLES media check
list all suse installation dirs
update comments
SUSE-Cloud-5-SLE12-* -> SLE12-Cloud-5-Compute-*
do not copy&paste
check both main installation repositories
Merge pull request #2068 from jsuchome/sle12

adding SLE12 based repositories
do not check for metadata yet
Merge pull request #2069 from jsuchome/sle12

do not check for metadata yet
Make SLE12 media optional

We currently do not want to require SLES12 media for
install.
Merge pull request #2070 from dirkmueller/master

Make SLE12 media optional
Merge pull request #2060 from vuntz/json-edit-array

Make json-edit able to edit attributes that are arrays