How to remove "pending update"?
I've never done this before so I'm not sure if this will work but I assume you can manually update the schema_version column in the {system} table to the highest hook_update_N number. For example if there's mymodule_update_7101 in the .install file of mymodule then update the schema_version column of the system table for mymodule to 7101.

I don't get it though, how come if you have updated fields in the module table of same database, how is it that the system table is older?