Log Message:
Update libetpan to version 1.7.2.
patch-src_low-level_smtp_mailsmtp.c has been
removed this change is included in this release.

Changelog:
1.7.2:
    Fixed so name for Linux

1.7:
Build
    Fixed expat / curl detection
    Fix build on OpenIndiana
    Support for Berkeley DB 6.0
    Support for Bitcode (Apple)
    Build for Android
    Improved build for Windows

General
    Support for socks proxy
    API for partial base64 parsing

SMTP
    Ability to cancel SMTP operations
    Fixed logging privacy with OAuth2 on smtp

IMAP
    Broken date parsing
    Improved latest TLS/SSL support
    IMAP MOVE implemented
    workaround for XLIST on cyon.ch
    Added ability to send custom IMAP command support
    Workaround for qq.com IMAP server
    Workaround for 163 IMAP server
    Improved SEARCH compatibility