[DRE-maint] Bug#802132: ruby-rack-oauth2: FTBFS: Could not find 'httpclient' (>= 2.4) - did find: [httpclient-2.3.3] (Gem::LoadError)

[Chris West (Faux)]

Source: ruby-rack-oauth2
Version: 1.2.0-3
Severity: serious
Justification: fails to build from source
Tags: sid stretch
User: reproducible-builds at lists.alioth.debian.org
Usertags: ftbfs
X-Debbugs-CC: reproducible-builds at lists.alioth.debian.org

Dear Maintainer,

The package fails to build:

┌──────────────────────────────────────────────────────────────────────────────┐
│ Checking Rubygems dependency resolution on ruby2.1                           │
└──────────────────────────────────────────────────────────────────────────────┘

GEM_PATH=/tmp/.gem/ruby/2.1.0:/var/lib/gems/2.1.0:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.1.0:/usr/share/rubygems-integration/2.1.0:/usr/share/rubygems-integration/2.1:/usr/share/rubygems-integration/all:debian/ruby-rack-oauth2/usr/share/rubygems-integration/all ruby2.1 -e gem\ \"rack-oauth2\"
/usr/lib/ruby/2.1.0/rubygems/dependency.rb:298:in `to_specs': Could not find 'httpclient' (>= 2.4) - did find: [httpclient-2.3.3] (Gem::LoadError)
	from /usr/lib/ruby/2.1.0/rubygems/specification.rb:1295:in `block in activate_dependencies'
	from /usr/lib/ruby/2.1.0/rubygems/specification.rb:1284:in `each'
	from /usr/lib/ruby/2.1.0/rubygems/specification.rb:1284:in `activate_dependencies'
	from /usr/lib/ruby/2.1.0/rubygems/specification.rb:1266:in `activate'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_gem.rb:54:in `gem'
	from -e:1:in `<main>'

Full build log:
https://reproducible.debian.net/rb-pkg/unstable/amd64/ruby-rack-oauth2.html

-- System Information:
Debian Release: stretch/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)