[Analyzer] Avoid loading specs when determining deps to fetch

lib/cocoapods/installer/analyzer.rb

@@ -748,7 +748,7 @@ module Pod
             deps_to_fetch = deps_with_external_source.select { |dep| pods_to_fetch.include?(dep.root_name) }
             deps_to_fetch_if_needed = deps_with_external_source.select { |dep| result.podfile_state.unchanged.include?(dep.root_name) }
             deps_to_fetch += deps_to_fetch_if_needed.select do |dep|
-              sandbox.specification(dep.root_name).nil? ||
+              sandbox.specification_path(dep.root_name).nil? ||
                 !dep.external_source[:path].nil? ||
                 !sandbox.pod_dir(dep.root_name).directory? ||
                 checkout_requires_update?(dep)