redundant file open error messages with fmpopen.c

[wehimwich]

From #45:

07:29:44?ERROR fm -1 Opening file: /usr2/proc/nothing.prc
07:29:44?ERROR bo -133 Error opening procedure library, UNIX 2: No such
file or directory

Added in a2f6bbc, while removing a non-logged error message when used with the FS, i.e., in a program that is "online". This was being conservative to avoid a silent error in case the caller did not handle the error. In fact, everywhere it is used in a FS online (i.e. not stand-alone), the error is logged normally, except aquir, where it could be fixed up easily (there are lots of other non-logged fmpsee/ errors though). In the case of aquir, this was a by-product of how it was incompletely promoted from an external to an internal FS program in 1ae556d. I can remember both of those errors, but finding them in the history with blame was relatively easy; especially since the second was apparently more about 25 years ago.