[api] Handle multibuilds in API call to _result

Fixes openSUSE#3026

In case of multibuilds we need to fetch the sources of the package
container, but the build results of the queried multibuild package.
This commit should do the trick.

Kudos to Michael for pointing me towards the right direction.

src/api/app/controllers/build_controller.rb

@@ -168,12 +168,19 @@ def result
   def result_lastsuccess
     required_parameters :package, :pathproject
 
-    pkg = Package.get_by_project_and_name(params[:project], params[:package],
+    if params[:multibuild]
+      partition = params[:package].rpartition(':')
+      package = partition.first
+      multibuild_suffix = partition.last
+    else
+      package = params[:package]
+    end
+    pkg = Package.get_by_project_and_name(params[:project], package,
                                           {use_source: false, follow_project_links: true})
     raise RemoteProjectError, 'The package lifes in a remote project, this is not supported atm' unless pkg
 
     tprj = Project.get_by_name params[:pathproject]
-    bs = PackageBuildStatus.new(pkg).result(target_project: tprj, srcmd5: params[:srcmd5])
+    bs = PackageBuildStatus.new(pkg).result(target_project: tprj, srcmd5: params[:srcmd5], multibuild_suffix: multibuild_suffix)
     @result = []
     bs.each do |repo, status|
       archs = []

src/api/app/models/package_build_status.rb

@@ -13,6 +13,7 @@ def initialize(pkg)
 
   def result(opts = {})
     @srcmd5 = opts[:srcmd5]
+    @multibuild_suffix = opts[:multibuild_suffix]
     gather_md5sums
 
     tocheck_repos = @pkg.project.repositories_linking_project(opts[:target_project])
@@ -90,8 +91,9 @@ def current_dir
   def gather_current_buildcode(srep, arch)
     @buildcode = "unknown"
     begin
+      package = CGI.escape([@pkg.name, @multibuild_suffix].join(':'))
       # rubocop:disable Metrics/LineLength
-      uri = URI("/build/#{CGI.escape(@pkg.project.name)}/_result?package=#{CGI.escape(@pkg.name)}&repository=#{CGI.escape(srep['name'])}&arch=#{CGI.escape(arch)}")
+      uri = URI("/build/#{CGI.escape(@pkg.project.name)}/_result?package=#{package}&repository=#{CGI.escape(srep['name'])}&arch=#{CGI.escape(arch)}")
       # rubocop:enable Metrics/LineLength
       resultlist = Xmlhash.parse(ActiveXML.backend.direct_http(uri))
       currentcode = nil