[ErrorReport] Make more robust against missing executables

Closes #3719

CHANGELOG.md

@@ -90,6 +90,10 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
   Mac App Store.  
   [Samuel Giddins](https://github.com/segiddins)
 
+* The error report template is now more robust against missing executables.  
+  [Samuel Giddins](https://github.com/segiddins)
+  [#3719](https://github.com/CocoaPods/CocoaPods/issues/3719)
+
 
 ## 0.37.2
 

lib/cocoapods/user_interface/error_report.rb

@@ -73,6 +73,12 @@ EOS
 
         private
 
+        def `(command)
+          super
+        rescue Errno::ENOENT => e
+          "Unable to find an executable (#{e})"
+        end
+
         def pathless_exception_message(message)
           message.gsub(/- \(.*\):/, '-')
         end