Sign 1.6.0~rc1 testing

1.6.0~rc1/sysupgrade/testing.manifest

@@ -291,3 +291,4 @@ x86-64 1.6.0~rc1 a5da9e1c8c16b6dfbb588a84b3505cd4b855b811638879a080633cab757a287
 ---
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 a993c1a112f5ebd90eba9dc8fd9f9a9e5a9a8dbe2e8348640290798b98ef2a03ff469d010cf6daa186fd7e4b19ca44b93529a2d02aa0974f98bc61182b183302
+b1a4e5bcb5924ec89e93af707fdcfca193dac9e026cf853bcdab3c7f2f12e00cef38d2087219c1b8dbbb96856aa834f4e07241d44d18fa968da0a0bd0858d101