Log Message:
nss: Update to 3.49

Changelog:
Notable Changes in NSS 3.49
 * The legacy DBM database, libnssdbm, is no longer built by default when
using gyp builds. See Bug 1594933 for details.

Bugs fixed in NSS 3.49
 * Bug 1513586 - Set downgrade sentinel for client TLS versions lower than
1.2.
 * Bug 1606025 - Remove -Wmaybe-uninitialized warning in sslsnce.c
 * Bug 1606119 - Fix PPC HW Crypto build failure
 * Bug 1605545 - Memory leak in Pk11Install_Platform_Generate
 * Bug 1602288 - Fix build failure due to missing posix signal.h
 * Bug 1588714 - Implement CheckARMSupport for Win64/aarch64
 * Bug 1585189 - NSS database uses 3DES instead of AES to encrypt DB entries
 * Bug 1603257 - Fix UBSAN issue in softoken CKM_NSS_CHACHA20_CTR
initialization
 * Bug 1590001 - Additional HRR Tests (CVE-2019-17023)
 * Bug 1600144 - Treat ClientHello with message_seq of 1 as a second
ClientHello
 * Bug 1603027 - Test that ESNI is regenerated after HelloRetryRequest
 * Bug 1593167 - Intermittent mis-reporting potential security risk
SEC_ERROR_UNKNOWN_ISSUER
 * Bug 1535787 - Fix automation/release/nss-release-helper.py on MacOS
 * Bug 1594933 - Disable building DBM by default
 * Bug 1562548 - Improve GCM perfomance on aarch32