Fix failure in gdb.ada/complete.exp

Fix failure in gdb.ada/complete.exp

I noticed a failure in gdb.ada/complete.exp when testing locally:

    FAIL: gdb.ada/complete.exp: complete break ada

This failed due to this output:

    [...]
    break ada/generated/gnatvsn.ads
    break ada/libgnat/s-excmac.ads
    break ada/sdefault.adb
    break ada/snames.adb
    break ada/snames.ads

This patch updates the regexp to allow "/" and "-" to appear.

gdb/testsuite/ChangeLog
2019-05-29  Tom Tromey  <tromey@adacore.com>

	* gdb.ada/complete.exp (test_gdb_no_completion): Add "/" and "-"
	to "break complete ada" test case's regexp.