move check earlier

Author: leavez

lib/cocoapods-binary/Prebuild.rb

@@ -69,6 +69,10 @@ def install_when_cache_hit!
         # Build the needed framework files
         def prebuild_frameworks! 
 
+            # check
+            # give a early warning, instead of after compiling all the pods
+            Prebuild.check_one_pod_should_have_only_one_target(self.pod_targets)
+
             # build options
             sandbox_path = sandbox.root
             existed_framework_folder = sandbox.generate_framework_path
@@ -114,10 +118,6 @@ def prebuild_frameworks!
 
             targets = targets.reject {|pod_target| sandbox.local?(pod_target.pod_name) }
 
-            # check
-            # give a early warning, instead of after compiling all the pods
-            
-            Prebuild.check_one_pod_should_have_only_one_target(self.pod_targets)
 
             # build!
             Pod::UI.puts "Prebuild frameworks (total #{targets.count})"