ZOOKEEPER-3056: Fails to load database with missing snapshot file but with valid transaction log file.

[hanm]

This is a port of patch #1069

[eolivelli]

LGTM

[eolivelli]

retest maven build

[eolivelli]

ant build failed due to a problem on the machine:
BUILD FAILED
/home/jenkins/jenkins-slave/workspace/PreCommit-ZOOKEEPER-github-pr-build/build.xml:1802: 'findbugs.home' is not defined. Please pass -Dfindbugs.home= to Ant on the command-line.

retest ant build

[eolivelli]

retest ant build

[eolivelli]

@hanm @anmolnar @nkalmar @phunt

it seems that Maven build failed due to an upgrade of gcc on Jenkins slaves, we should address those problems in separate tasks

 [exec] /home/jenkins/jenkins-slave/workspace/PreCommit-ZOOKEEPER-github-pr-build-maven/zookeeper-client/zookeeper-client-c/src/zookeeper.c:2560:5: error: null argument where non-null required (argument 1) [-Werror=nonnull]
 [exec]      fprintf(LOGSTREAM,"Completion queue: ");
 [exec]      ^~~~~~~
 [exec] /home/jenkins/jenkins-slave/workspace/PreCommit-ZOOKEEPER-github-pr-build-maven/zookeeper-client/zookeeper-client-c/src/zookeeper.c:2562:9: error: null argument where non-null required (argument 1) [-Werror=nonnull]
 [exec]          fprintf(LOGSTREAM,"empty\n");
 [exec]          ^~~~~~~
 [exec] /home/jenkins/jenkins-slave/workspace/PreCommit-ZOOKEEPER-github-pr-build-maven/zookeeper-client/zookeeper-client-c/src/zookeeper.c:2568:9: error: null argument where non-null required (argument 1) [-Werror=nonnull]
 [exec]          fprintf(LOGSTREAM,"%d,",cptr->xid);
 [exec]          ^~~~~~~
 [exec] /home/jenkins/jenkins-slave/workspace/PreCommit-ZOOKEEPER-github-pr-build-maven/zookeeper-client/zookeeper-client-c/src/zookeeper.c:2571:5: error: null argument where non-null required (argument 1) [-Werror=nonnull]
 [exec]      fprintf(LOGSTREAM,"end\n");
 [exec]      ^~~~~~~
 [exec] Makefile:1032: recipe for target 'zookeeper.lo' failed
 [exec] cc1: all warnings being treated as errors
 [exec] make: *** [zookeeper.lo] Error 1

and Ant build fails due to the fact that "findbugs" is missing

[eolivelli]

retest ant build
retest maven build

[hanm]

It should be ok to merge this as it's not the cause of the CI failures we observed here; plus the scope and impact of this patch is well understood.

Fixing of CI could be done on a separate track that's not blocking the release if we want to get the release out soon. I am ok either way. Your call @eolivelli.

[eolivelli]

Merged to branch-3.5.
We can fix CI stuff without hurry

[hanm]

merged as 77496b9