[backend] Obsoletes don't work on provides
[api] fix diffing on creating submit requests

The case when target package exists and source package is remote
[backend] enable vm watchdog in build script

Let's do it by default for all VM builds for now to avoid yet
another config option.
[api] don't crash when trying to submit to remote instance
[backend] allow to specify external pool repository URLs.

bnc#884270
[backend] ignore frozenlink if a specific srcmd5 is requested
[backend] Add Debian ppc64el architecture to debarches

Debian based distros have different name for PowerPC 64Bit Little Endian
architecture.

Signed-off-by: Dinar Valeev <dvaleev@suse.com>
[backend] write PRODUCT_RELEASE only for SLE12 media style
[backend] export pool repository URL also in productrepositorylist

bnc#884270
[webui][api] Refactor attributes