build: remove default provider priority

build: remove default provider priority

Remove default provider priority since packages are expected to
explicitly declare virtual provides and set default variants. With
default priority some package variants without PROVIDES and not marked
as default end up with priority 0 and are not picked for installation.

Before the change dnsmasq-dhcpv6 is selected for dnsmasq, because the
former has higher priority:

name <dnsmasq> selected from selectable list
select_package: dnsmasq (requirers=1, autosel=1, iif=0, order_id=0x4000005f)
  consider dnsmasq-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=0, installed=0
   prefer existing package
    choose as new provider
  consider dnsmasq-dhcpv6-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=1, installed=0
    prefer highest declared provider priority
    choose as new provider
  consider dnsmasq-full-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=1, installed=0
    prefer lowest available repository
selecting: dnsmasq-dhcpv6-2.91-r2, available: 1
assign dnsmasq-dhcpv6 to dnsmasq-dhcpv6-2.91-r2
assign dnsmasq to dnsmasq-dhcpv6-2.91-r2
disqualify_package: dnsmasq-2.91-r2 (conflicting provides)
disqualify_package: dnsmasq-full-2.91-r2 (conflicting provides)
    apply_constraint: libc
    apply_constraint: provider: libc-1.2.5-r5: 1

After the change dnsmasq is selected for dnsmasq based on
lexicographical order:

name <dnsmasq> selected from selectable list
select_package: dnsmasq (requirers=1, autosel=1, iif=0, order_id=0x4000005f)
  consider dnsmasq-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=0, installed=0
   prefer existing package
    choose as new provider
  consider dnsmasq-dhcpv6-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=0, installed=0
    prefer lowest available repository
  consider dnsmasq-full-2.91-r2 iif_triggered=0, tag_ok=1, selectable=1, available=1, flags=0x0, provider_priority=0, installed=0
    prefer lowest available repository
selecting: dnsmasq-2.91-r2, available: 1
assign dnsmasq to dnsmasq-2.91-r2
disqualify_package: dnsmasq-dhcpv6-2.91-r2 (conflicting provides)
disqualify_package: dnsmasq-full-2.91-r2 (conflicting provides)
    apply_constraint: libc
    apply_constraint: provider: libc-1.2.5-r5: 1

Fixes: dea8397 ("include/package-pack: add default 'provider_priority' for APK packages")
Signed-off-by: George Sapkin <george@sapk.in>
Link: https://github.com/openwrt/openwrt/pull/21369
Signed-off-by: Robert Marko <robimarko@gmail.com>