Update ancient copyright string in -version output

Update ancient copyright string in -version output

Currently the -version command line argument prints a string ending
with "Copyright (c) 2003-2008 Fabrice Bellard".  This is now some
eight years out of date; abstract it out of the several places that
print the string and update it to:

Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers

to reflect the work by all the QEMU Project contributors over the
last decade.

Signed-off-by: Peter Maydell <[email protected]>
Acked-by: Stefan Hajnoczi <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Message-id: 1470309276[email protected]