bpf: switch map/prog selinux_context field from storing 'fs_bpf_foo' to 'foo/'

This will eliminate the need for domain stuff.

After this:
  git grep fs_bpf_
finds nothing but comments.

Test: TreeHugger
Flag: EXEMPT no-op
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ie834e9b2b120ee772690b28457c1ff080cb914dd
diff --git a/bpf/loader/NetBpfLoad.cpp b/bpf/loader/NetBpfLoad.cpp
index 6ccd748..79583bd 100644
--- a/bpf/loader/NetBpfLoad.cpp
+++ b/bpf/loader/NetBpfLoad.cpp
@@ -151,12 +151,12 @@
 constexpr const char* lookupSelinuxContext(const domain d) {
     switch (d) {
         case domain::unspecified:   return "";
-        case domain::tethering:     return "fs_bpf_tethering";
-        case domain::net_private:   return "fs_bpf_net_private";
-        case domain::net_shared:    return "fs_bpf_net_shared";
-        case domain::netd_readonly: return "fs_bpf_netd_readonly";
-        case domain::netd_shared:   return "fs_bpf_netd_shared";
-        case domain::loader:        return "fs_bpf_loader";
+        case domain::tethering:     return "tethering/";
+        case domain::net_private:   return "net_private/";
+        case domain::net_shared:    return "net_shared/";
+        case domain::netd_readonly: return "netd_readonly/";
+        case domain::netd_shared:   return "netd_shared/";
+        case domain::loader:        return "loader/";
     }
 }