storaged: add storaged_pri service

"storaged" service will be used by external clients, e.g. vold, dumpsys
"storaged_pri" service will only be used by storaged cmdline.

Bug: 63740245
Change-Id: I7a60eb4ce321aced9589bbb8474d2d9e75ab7042
(cherry picked from commit 37ab7c09)

prebuilts/api/26.0/private/service_contexts

@@ -142,6 +142,7 @@ sip                                       u:object_r:radio_service:s0
 soundtrigger                              u:object_r:voiceinteraction_service:s0
 statusbar                                 u:object_r:statusbar_service:s0
 storaged                                  u:object_r:storaged_service:s0
+storaged_pri                              u:object_r:storaged_service:s0
 storagestats                              u:object_r:storagestats_service:s0
 SurfaceFlinger                            u:object_r:surfaceflinger_service:s0
 task                                      u:object_r:task_service:s0

private/service_contexts

@@ -153,6 +153,7 @@ statscompanion                            u:object_r:statscompanion_service:s0
 soundtrigger                              u:object_r:voiceinteraction_service:s0
 statusbar                                 u:object_r:statusbar_service:s0
 storaged                                  u:object_r:storaged_service:s0
+storaged_pri                              u:object_r:storaged_service:s0
 storagestats                              u:object_r:storagestats_service:s0
 SurfaceFlinger                            u:object_r:surfaceflinger_service:s0
 system_update                             u:object_r:system_update_service:s0