Update string expected from "help info proc" on gdb.base/info-proc.exp

Commit 73f1bd76 ("Make the "info proc" documentation more
consistent.") updated the output from "help info proc", but forgot to
update the test on gdb.base/info-proc.exp.  This obvious patch does
that.

Checked-in as obvious.

gdb/testsuite/ChangeLog:
2018-10-06  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/info-proc.exp: Update string expected from "help info
	proc".