TLS: fix some use-of-uninitialized-value errors in ClientHello parsing (#1169)

Error detected with valgrind.

==125883== Conditional jump or move depends on uninitialised value(s)
==125883==    at 0x438F57: processClientServerHello (tls.c:1421)
==125883==    by 0x43B35A: processTLSBlock (tls.c:712)
==125883==    by 0x43B1C4: ndpi_search_tls_tcp (tls.c:849)
==125883==    by 0x42C60B: check_ndpi_detection_func (ndpi_main.c:4426)
==125883==    by 0x42E920: ndpi_detection_process_packet (ndpi_main.c:5301)

==125916== Conditional jump or move depends on uninitialised value(s)
==125916==    at 0x438D7D: processClientServerHello (tls.c:1379)
==125916==    by 0x43B35A: processTLSBlock (tls.c:712)
==125916==    by 0x43B1C4: ndpi_search_tls_tcp (tls.c:849)
==125916==    by 0x42C60B: check_ndpi_detection_func (ndpi_main.c:4426)

==125932== Conditional jump or move depends on uninitialised value(s)
==125932==    at 0x438C1D: processClientServerHello (tls.c:1298)
==125932==    by 0x43B35A: processTLSBlock (tls.c:712)
==125932==    by 0x43B1C4: ndpi_search_tls_tcp (tls.c:849)
==125932==    by 0x42C60B: check_ndpi_detection_func (ndpi_main.c:4426)

==125950== Conditional jump or move depends on uninitialised value(s)
==125950==    at 0x438D4F: processClientServerHello (tls.c:1371)
==125950==    by 0x43B35A: processTLSBlock (tls.c:712)
==125950==    by 0x43B1C4: ndpi_search_tls_tcp (tls.c:849)
==125950==    by 0x42C079: check_ndpi_detection_func (ndpi_main.c:4443)

1 files changed, 0 insertions, 0 deletions

diff --git a/tests/pcap/tls_invalid_reads.pcap b/tests/pcap/tls_invalid_reads.pcap
new file mode 100644
index 000000000..4979428be
--- /dev/null
+++ b/tests/pcap/tls_invalid_reads.pcap