Update installation.md
Update installation.md

Updated the version of Git used in the section for compiling Git from source.

Also, changed the verbiage used in the section "Initialize Database and Activate Advanced Features". It previously said to type 'yes' to install the database.
8thcolor/rubyconfau2015-sadr,8thcolor/eurucamp2014-htdsadr,8thcolor/eurucamp2014-htdsadr,8thcolor/eurucamp2014-htdsadr,8thcolor/rubyconfau2015-sadr,8thcolor/rubyconfau2015-sadr