[REG 4.7.x->4.8.0] When switching the NDK to use r18b it will change kits that use gcc compilers and lose the compiler setting

[REG 4.7.x->4.8.0] When switching the NDK to use r18b it will change kits that use gcc compilers and lose the compiler setting. This is because NDK r18b has no gcc compilers available, so it should leave the kits that are set to use android-gcc alone and not change the existing ones. Which would therefore enable users to switch the NDKs used if necessary.

This also effects manually added kits and not just automatic ones