[Target] Extract default build configurations into a constant

lib/cocoapods/installer/analyzer.rb

@@ -441,7 +441,7 @@ module Pod
           user_project = nil
           client_root = config.installation_root.realpath
           user_target_uuids = []
-          user_build_configurations = target_definition.build_configurations || { 'Release' => :release, 'Debug' => :debug }
+          user_build_configurations = target_definition.build_configurations || Target::DEFAULT_BUILD_CONFIGURATIONS
           archs = []
           if target_definition.platform && target_definition.platform.name == :osx
             archs = ['$(ARCHS_STANDARD_64_BIT)']

lib/cocoapods/target.rb

@@ -10,6 +10,7 @@ module Pod
   class Target
     DEFAULT_VERSION = '1.0.0'.freeze
     DEFAULT_NAME = 'Default'.freeze
+    DEFAULT_BUILD_CONFIGURATIONS = { 'Release' => :release, 'Debug' => :debug }.freeze
 
     # @return [Sandbox] The sandbox where the Pods should be installed.
     #

spec/spec_helper.rb

@@ -146,7 +146,7 @@ def fixture_pod_target_with_specs(specs, host_requires_frameworks = false, user_
                      target_definitions, file_accessors, scope_suffix)
 end
 
-def fixture_aggregate_target(pod_targets = [], host_requires_frameworks = false, user_build_configurations = { 'Release' => :release },
+def fixture_aggregate_target(pod_targets = [], host_requires_frameworks = false, user_build_configurations = Pod::Target::DEFAULT_BUILD_CONFIGURATIONS,
                              archs = [], platform = Pod::Platform.new(:ios, '6.0'), target_definition = nil)
   target_definition ||= pod_targets.flat_map(&:target_definitions).first || fixture_target_definition
   Pod::AggregateTarget.new(config.sandbox, host_requires_frameworks, user_build_configurations, archs, platform,