debian: do not build with -buildmode=pie on i386 (2.27)

[mvo5]

With -buildmode=pie mode on i386 snapd panics in spectacular
ways (LP: #1711052) so we need to disable it for the time
being.

See also https://forum.snapcraft.io/t/artful-i386-panics/

[codecov-io]

Codecov Report

Merging #3737 into release/2.27 will decrease coverage by <.01%.
The diff coverage is n/a.

@@               Coverage Diff                @@
##           release/2.27    #3737      +/-   ##
================================================
- Coverage         74.87%   74.86%   -0.01%     
================================================
  Files               382      382              
  Lines             32995    32995              
================================================
- Hits              24704    24701       -3     
- Misses             6490     6493       +3     
  Partials           1801     1801

Impacted Files	Coverage Δ
cmd/snap/cmd_aliases.go	93.33% <0%> (-1.67%)	⬇️
overlord/ifacestate/helpers.go	62.33% <0%> (-0.67%)	⬇️
interfaces/sorting.go	94.28% <0%> (ø)	⬆️

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[mwhudson]

Seems fine and pragmatic

[mwhudson]

It's not really important but you don't need to set -pkgdir unless you are also setting -buildmode=pie

[mvo5]

Aha, nice! I was not aware of this

[mwhudson]

As I mentioned on IRC, this should be dpkg-architecture -qDEB_TARGET_ARCH or something like that

[mvo5]

Thanks, silly me. Fixed.

[chipaca]

if you happen to commit again to this, tidy the language a bit :-) (as can panics?)

[mvo5]

cough thank you