dragon: crash_collector use getpwnam()

Use getpwnam() instead of android_ids[] array.

(cherrypick of aba3ddcc7f743f0315cfa2913e17f1059ef54973 from internal master for http://b/33502258)

Bug: 27999086
Change-Id: If66274083bc36d159505bd2a25acb7f17ac40bf7
1 file changed