crash_reporter: Use the actual GID of the crashing process

Rather than assuming the UID and GID of crashing processes is
the same, report and use the actual GID that the process was
running as.

Bug: 24678424
Change-Id: I3cfc415be2feb2863a4f4b850bfd4a3267217a44
diff --git a/crash_reporter/crash_reporter.rc b/crash_reporter/crash_reporter.rc
index 5fb0d7a..7bfe0c2 100644
--- a/crash_reporter/crash_reporter.rc
+++ b/crash_reporter/crash_reporter.rc
@@ -1,6 +1,6 @@
 on property:crash_reporter.coredump.enabled=1
     write /proc/sys/kernel/core_pattern \
-          "|/system/bin/crash_reporter --user=%P:%s:%u:%e"
+          "|/system/bin/crash_reporter --user=%P:%s:%u:%g:%e"
 
 on property:crash_reporter.coredump.enabled=0
     write /proc/sys/kernel/core_pattern "core"