security/libgcrypt: update to 1.7.7

• Update libgcrypt to 1.7.7
• Silence all explicitly called commands
• Update WWW in pkg-descr: use https://
• Bump library version in pkg-plist

Noteworthy changes in version 1.7.7

• Bug fixes:
  • Fix possible timing attack on EdDSA session key.
  • Fix long standing bug in secure memory implementation which could lead to a segv on free. [bug#3027].

PR: 219747
MFH: 2017Q2
Exp-run by: antoine