perf tools: Fix the bash completion to support listing events for --event

The bash completion only supports -e rather than --event, so fix it.

Example:

Before this patch:

 $ perf record --event <TAB>
 $

As shown above, the events of record does not come out.

After this patch:

 $ perf record --event <TAB>
 lignment-faults                   cpu/instructions/
 L1-dcache-prefetch-misses          node-prefetches
 uncore_rbox_0/qpi0_idle_filt/
 branch-instructions                cpu/mem-loads/
 L1-dcache-store-misses             node-prefetch-misses
 uncore_rbox_0/qpi1_date_response/
 branch-load-misses                 cpu-migrations
 L1-dcache-stores                   node-store-misses
 uncore_rbox_0/qpi1_filt_send/
 branch-loads                       dTLB-load-misses
 L1-icache-load-misses              node-stores
 uncore_rbox_0/qpi1_idle_filt/
 ...

As shown above, the events of record can come out now.
Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1426685758-25488-6-git-send-email-yunlong.song@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/perf-completion.sh

@@ -137,8 +137,8 @@ __perf_main ()
 			cmds=$($cmd --list-cmds)
 		fi
 		__perfcomp "$cmds" "$cur"
-	# List possible events for -e option
-	elif [[ $prev == "-e" && $prev_skip_opts == @(record|stat|top) ]]; then
+	# List possible events for -e and --event option
+	elif [[ $prev == @("-e"|"--event") && $prev_skip_opts == @(record|stat|top) ]]; then
 		evts=$($cmd list --raw-dump)
 		__perfcomp_colon "$evts" "$cur"
 	else