Remove bogus PROVISIONING_PROFILE_SPECIFIER value from Pods project

This value breaks code signing on Xcode 9 using CODE_SIGN_IDENTITY environment variable

CHANGELOG.md

@@ -101,6 +101,10 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
   [Dimitris Koutsogiorgas](https://github.com/dnkoutso)
   [#7460](https://github.com/CocoaPods/CocoaPods/issues/7460)
 
+* Remove bogus `PROVISIONING_PROFILE_SPECIFIER` value from Pods project.  
+  [Ruenzuo](https://github.com/Ruenzuo)
+  [#6964](https://github.com/CocoaPods/CocoaPods/issues/6964)
+
 ## 1.4.0 (2018-01-18)
 
 ##### Enhancements

lib/cocoapods/installer/xcode/pods_project_generator.rb

@@ -153,7 +153,6 @@ module Pod
               build_configuration.build_settings['STRIP_INSTALLED_PRODUCT'] = 'NO'
               build_configuration.build_settings['CLANG_ENABLE_OBJC_ARC'] = 'YES'
               build_configuration.build_settings['CODE_SIGNING_REQUIRED'] = 'NO'
-              build_configuration.build_settings['PROVISIONING_PROFILE_SPECIFIER'] = 'NO_SIGNING/' # a bogus provisioning profile ID assumed to be invalid
             end
           end
         end