build.sh building succesfully, throwing some errors after build

[olayasturias]

There are still some removal of folders for "Airsim" (as it is the baseline plugin for UNavSim), but they dont exist because of the new naming of the plugin. The error message:

[100%] Linking CXX executable ../output/bin/AirLibUnitTests
[100%] Built target AirLibUnitTests
+ popd
+ mkdir -p AirLib/lib/x64/Release
+ mkdir -p AirLib/deps/rpclib/lib
+ mkdir -p AirLib/deps/MavLinkCom/lib
+ cp build_release/output/lib/libAirLib.a AirLib/lib
+ cp build_release/output/lib/libMavLinkCom.a AirLib/deps/MavLinkCom/lib
+ cp build_release/output/lib/librpc.a AirLib/deps/rpclib/lib/librpc.a
+ rsync -a --delete build_release/output/lib/ AirLib/lib/x64/Release
+ rsync -a --delete external/rpclib/rpclib-2.3.0/include AirLib/deps/rpclib
+ rsync -a --delete MavLinkCom/include AirLib/deps/MavLinkCom
+ rsync -a --delete AirLib Unreal/Plugins/AirSim/Source
+ rm -rf Unreal/Plugins/AirSim/Source/AirLib/src
+ for d in Unreal/Environments/*
+ '[' -L Unreal/Environments/Blocks ']'
+ Unreal/Environments/Blocks/clean.sh
+ rm -rf Binaries
+ rm -rf Intermediate
+ rm -rf Saved
+ rm -rf Plugins/AirSim/Binaries
+ rm -rf Plugins/AirSim/Intermediate
+ rm -rf Plugins/AirSim/Saved
+ rm -f CMakeLists.txt
+ rm -f Makefile
+ popd
+ mkdir -p Unreal/Environments/Blocks/Plugins
+ rsync -a --delete Unreal/Plugins/AirSim Unreal/Environments/Blocks/Plugins
rsync: readlink_stat("/home/freyja/Underwater_Simulator/UNav-Sim/Unreal/Plugins/AirSim/Content/VehicleAdv/SUV/AutomotiveMaterials/Textures") failed: Permission denied (13)
rsync: readlink_stat("/home/freyja/Underwater_Simulator/UNav-Sim/Unreal/Plugins/AirSim/Content/VehicleAdv/SUV/AutomotiveMaterials/Materials") failed: Permission denied (13)
IO error encountered -- skipping file deletion
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1207) [sender=3.1.3]