MOZILLA_CERTIFICATE_FOLDER needs to be non-empty to disable autodetect...

of the users profile. make CppunitTest_desktop_lib fails for me because
I have a real profile which is autodetected but which gives a
SEC_ERROR_TOKEN_NOT_LOGGED_IN failure if used. The intent here is
clearly to avoid doing an autodetect.

before

commit 02399a217b
Date:   Mon Dec 31 12:22:39 2018 +0100

    for tests MOZILLA_CERTIFICATE_FOLDER should be set to empty not 0

"0" was explicitly used

Change-Id: I0110d8e2c4c378dde75a1c8da3757bfa29f6c1b0
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/110424
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

solenv/gbuild/gbuild.mk

@@ -261,7 +261,18 @@ gb_GLOBALDEFS := $(sort $(gb_GLOBALDEFS))
 # * Cap the number of threads unittests use:
 gb_TEST_ENV_VARS := MAX_CONCURRENCY=4
 # * Disable searching for certificates by default:
-gb_TEST_ENV_VARS += MOZILLA_CERTIFICATE_FOLDER=
+#
+#  see xmlsecurity/source/xmlsec/nss/nssinitializer.cxx for use
+#
+#  a) If MOZILLA_CERTIFICATE_FOLDER is empty then LibreOffice autodetects
+#  the user's mozilla-decended application profile. To disable that we
+#  use a non-empty string here.
+#
+#  b) Using dbm: appears to nss as equivalent to an empty path so the
+#  initial NSS_InitReadWrite will fail. In response to that failure
+#  LibreOffice will create a temp fallback cert database which is removed
+#  on process exit
+gb_TEST_ENV_VARS += MOZILLA_CERTIFICATE_FOLDER=dbm:
 # Avoid hanging if the cups daemon requests a password:
 gb_TEST_ENV_VARS += SAL_DISABLE_SYNCHRONOUS_PRINTER_DETECTION=1
 ifeq (,$(SAL_USE_VCLPLUGIN))