Simplify complaints even more

Simplify complaints even more

This removes the SHORT_FIRST_MESSAGE case from complaints, leaving
only a single case.  This allows for the removal of the last argument
to clear_complaints, and also simplifies complaint_internal, removing
an extra allocation in the process.

After this, the "./gdb -iex 'set complaint 1' -nx ./gdb" example will
show:

    Reading symbols from ./gdb...
    During symbol reading: .debug_ranges entry has start address of zero [in module /home/tromey/gdb/build/gdb/gdb]
    During symbol reading: DW_AT_low_pc 0x0 is zero for DIE at 0x17116c1 [in module /home/tromey/gdb/build/gdb/gdb]
    During symbol reading: .debug_line address at offset 0xa22f5 is 0 [in module /home/tromey/gdb/build/gdb/gdb]
    During symbol reading: unsupported tag: 'DW_TAG_unspecified_type'
    During symbol reading: const value length mismatch for 'std::ratio<1, 1000000000>::num', got 8, expected 0

This is a bit wordier but, I think, a bit more clear, as the form of
the message no longer depends on precisely when it was emitted.  In
particular if you compare to the output from the 'Clean up "Reading
symbols" output' patch, you can see that earlier gdb would switch from
the prefix-less form to the "During symbol reading" form at a point
that is meaningless to the user (specifically, after psymtab reading
is done and gdb tries to expand a CU).

2018-10-04  Tom Tromey  <tom@tromey.com>

	* symfile.c (syms_from_objfile_1, finish_new_objfile)
	(reread_symbols): Update.
	* complaints.h (clear_complaints): Remove argument.
	* complaints.c (enum complaint_series): Remove.
	(series): Remove global.
	(complaint_internal): Update.
	(clear_complaints): Remove argument.

gdb/testsuite/ChangeLog
2018-10-04  Tom Tromey  <tom@tromey.com>

	* gdb.cp/maint.exp (test_invalid_name): Update expected output.
	* gdb.gdb/complaints.exp (test_short_complaints): Remove.
	(test_initial_complaints, test_empty_complaints): Update.
	* gdb.dwarf2/dw2-stack-boundary.exp: Update.