cros_workon: fix comments/messages to be consistent with new location

cros_workon has move to /usr/bin/

BUG=11507
TEST=none

Change-Id: I7301f659900713c432104ccceb3e658218e0ecac

Review URL: http://codereview.chromium.org/6334137
diff --git a/bash_completion b/bash_completion
index bc9988a..0ff38e4 100644
--- a/bash_completion
+++ b/bash_completion
@@ -133,7 +133,7 @@
 # TODO(petkov): Currently, this assumes that the command is the first
 # argument. In practice, the command is the first non-flag
 # argument. I.e., this should be fixed to support something like
-# "./cros_workon --all list".
+# "cros_workon --all list".
 _complete_cros_workon_command() {
   [ ${COMP_CWORD} -eq 1 ] || return 1
   local command="${COMP_WORDS[1]}"