Add an installd command to prune dex files.

This is a straightforward port of logic from
PackageManagerService#pruneDexFiles.

bug: 14407732

Change-Id: I892cff027ddcbb1a4fb37a7af5ecf1697049a188
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index 10bf5fa..6775284 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -135,6 +135,12 @@
                              /* pkgName, seinfo, uid*/
 }
 
+static int do_prune_dex_cache(char **arg __attribute__((unused)),
+                              char reply[REPLY_MAX] __attribute__((unused)))
+{
+    return prune_dex_cache();
+}
+
 struct cmdinfo {
     const char *name;
     unsigned numargs;
@@ -160,6 +166,7 @@
     { "rmuser",               1, do_rm_user },
     { "idmap",                3, do_idmap },
     { "restorecondata",       3, do_restorecon_data },
+    { "prunedexcache",        0, do_prune_dex_cache },
 };
 
 static int readx(int s, void *_buf, int count)