Merge pull request #447 from NickLaMuro/fix_source_for_log_errors

[MiqGenericMountSession] Fix .source_for_log

(cherry picked from commit bb0b1d4)

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1767895

lib/gems/pending/util/mount/miq_generic_mount_session.rb

@@ -490,6 +490,12 @@ def settings_mount_point
   end
 
   def source_for_log
-    @input_writer ? "<STREAMED_FROM_CMD>" : @source_input.path
+    if @input_writer
+      "<STREAMED_FROM_CMD>"
+    elsif @source_input
+      @source_input.path
+    else
+      "<NOT_READY>"
+    end
   end
 end