README: Fix dependencies

* Remove the dependency on Git (which can be obtained automatically when
  building, using either the Git submodule or `make get-git`).

* Use proper upstream names of dependencies.

Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>

README

@@ -35,10 +35,9 @@ file (see the Makefile for details).
 Dependencies
 ------------
 
-* git 1.7.4
-* zip lib
-* crypto lib
-* openssl lib
+* libzip
+* libcrypto (OpenSSL)
+* libssl (OpenSSL)
 
 Apache configuration
 --------------------