After succeeding openSessionCommon(), when the call to
getSecurityLevel() fails, the code calls closeSession()
and only clears the sessionId if closeSession() fails.
We should always clear sessionId in this case.
Also, make it clearer that the status returned by
getSecurityLevel() does not overwrite the value from
openSessionCommon().
Merged from http://go/wvgerrit/95845
Test: unit test
adb shell LD_LIBRARY_PATH="/vendor/lib64" /data/nativetest/libwvdrmdrmplugin_hidl_test
Bug: 151364587
Change-Id: I3a9106ffa44c654d3e072a0b0597398d410fc84f