nimble/host: Fix stopping host with pending connections #3

Job	Run time
Build GCC test target (ubuntu-latest, 13.2.Rel1)	4m 38s
Build GCC test target (ubuntu-latest, 8-2019-q3)	5m 16s
Build GCC test target (ubuntu-latest, 12.2.Rel1)	4m 16s
Build GCC test target (ubuntu-latest, 10.3-2021.10)	4m 27s
Build GCC test target (ubuntu-latest, 11.3.Rel1)	7m 44s
Build GCC test target (ubuntu-latest, 9-2020-q2)	4m 39s
	31m 0s

Provide feedback