Add guards to xrdp_mm_module_cleanup #2101

Job	Run time
cppcheck	18m 50s
code formatting check	21s
min features with gcc	2m 20s
min features with g++	2m 58s
min features with clang	2m 51s
max features with gcc	3m 36s
max features with g++	2m 56s
max features with clang	3m 44s
max features with clang and AddressSanitized	2m 51s
max features with gcc and DEBUG	2m 8s
max features with gcc for 32-bit arch (legacy OS)	1m 36s
max features with g++ for 32-bit arch (legacy OS)	2m 16s
max features with clang for 32-bit arch (legacy OS)	1m 59s
	48m 26s

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