Fix bunch of coverity issues. #3909

Job	Run time
cmake-offline-googletest	5m 2s
cmake-offline-googletest-src	4m 18s
system-sexpp, sexpp shared libs on, rnp shared libs on	3m 0s
system-sexpp, sexpp shared libs on, rnp shared libs off	3m 18s
package-source	36s
system-sexpp, sexpp shared libs off, rnp shared libs on	2m 55s
ubuntu-latest [CC gcc; botan; shared libs on; GnuPG stable]	4m 28s
system-sexpp, sexpp shared libs off, rnp shared libs off	3m 50s
ubuntu-latest [CC clang; botan; shared libs on; GnuPG stable]	4m 44s
ubuntu-latest [CC gcc; openssl; shared libs on; GnuPG stable]	4m 43s
ubuntu-latest [CC clang; openssl; shared libs on; GnuPG stable]	4m 28s
ubuntu-20.04 [CC gcc; openssl; shared libs on; GnuPG stable]	4m 1s
ubuntu-latest [CC gcc; botan; shared libs off; GnuPG stable]	4m 43s
package	57s
debian-tests	1m 7s
	52m 10s

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