[DocDB] FATAL when setting webserver_certificate_file gflag

[es1024]

Jira Link: DB-2981

Description

Reported by @charleswang234

When the webserver_certificate_file gflag is set, we get FATALs such as:

I0715 23:10:01.882122  8523 webserver.cc:183] Webserver: Enabling HTTPS support
I0715 23:10:01.882144  8523 webserver.cc:163] Webserver listen spec is 10.9.77.69:9000s
I0715 23:10:01.882987  8523 webserver.cc:343] Webserver: load_dll: cannot load libssl.so.10
F0715 23:10:01.888303  8523 tablet_server_main.cc:208] Network error (yb/server/webserver.cc:244): Webserver: Could not start on address 10.9.77.69:9000

or

I0718 08:19:42.216615 472376 webserver.cc:186] Webserver: Enabling HTTPS support
I0718 08:19:42.216748 472376 webserver.cc:166] Webserver listen spec is 127.0.0.1:7000s
I0718 08:19:42.216991 472376 webserver.cc:346] Webserver: load_dll: libssl.so: cannot find SSLv23_server_method
W0718 08:19:42.217025 472376 net_util.cc:523] Failed to bind to 0.0.0.0:7000. Trying to use lsof to find any processes listening on the same port:
I0718 08:19:42.217041 472376 net_util.cc:526] $ export PATH=$PATH:/usr/sbin ; lsof -n -i 'TCP:7000' -sTCP:LISTEN ; for pid in $(lsof -F p -n -i 'TCP:7000' -sTCP:LISTEN | cut -f 2 -dp) ; do  while [ $pid -gt 1 ] ; do    ps h -fp $pid ;    pid=$(sed 's/.* (.*) [^ ] \([0-9]*\).*/\1/g' /proc/$pid/stat);  done ; done
W0718 08:19:42.558524 472376 net_util.cc:533]
F0718 08:19:42.558645 472376 master_main.cc:132] Network error (yb/server/webserver.cc:247): Webserver: Could not start on address 127.0.0.1:7000

This is due to how the version of Squeasel we use handles HTTPS:

1. Squeasel searches for OpenSSL itself with a hardcoded list, rather than using the one we bundle with thirdparty https://github.com/yugabyte/squeasel/blob/8ac777a122fccf0358cb8562e900f8e9edd9ed11-yb/squeasel.c#L158,L174
2. It tries to load SSL functions by itself from OpenSSL, including SSLv23_... methods, which as of OpenSSL 1.1.0 are no longer symbols in the library, but macros to TLS_... methods

These both stem from using an old version of Squeasel, and appear to be resolved on master. We should use a more recent version of Squeasel.

[es1024]

Resolved with f2702bb