Fix install instructions for Ubuntu.
Fix install instructions for Ubuntu.

Not only "libsqlite3-dev" is required, but also "sqlite3". Otherwise
compilation on Ubuntu 12.04 64bit fails with:

    sqlite3 tests/config.sqlite < src/config/config.sql
    /bin/sh: 1: sqlite3: not found

mongrel2/mongrel2,elo80ka/mongrel2,krakensden/mongrel2,pjkundert/mongrel2,aidenkeating/mongrel2,jiffyjeff/mongrel2,apjanke/mongrel2,jablkopp/mongrel2,mongrel2/mongrel2,apjanke/mongrel2,apjanke/mongrel2,mongrel2/mongrel2,apjanke/mongrel2,mongrel2/mongrel2,elo80ka/mongrel2,jdesgats/mongrel2,aidenkeating/mongrel2,pjkundert/mongrel2,chickenkiller/mongrel2,fanout/mongrel2,aidenkeating/mongrel2,apjanke/mongrel2,musl/mongrel2,jiffyjeff/mongrel2,musl/mongrel2,fanout/mongrel2,cpick/mongrel2,chickenkiller/mongrel2,cpick/mongrel2,pjkundert/mongrel2,jasom/mongrel2,musl/mongrel2,elo80ka/mongrel2,jablkopp/mongrel2,jablkopp/mongrel2,jasom/mongrel2,jasom/mongrel2,chickenkiller/mongrel2,jablkopp/mongrel2,aidenkeating/mongrel2,cpick/mongrel2,fanout/mongrel2,jdesgats/mongrel2,krakensden/mongrel2,cpick/mongrel2,chickenkiller/mongrel2,elo80ka/mongrel2,aidenkeating/mongrel2,mongrel2/mongrel2,mongrel2/mongrel2,jdesgats/mongrel2,jiffyjeff/mongrel2,chickenkiller/mongrel2,jiffyjeff/mongrel2,aidenkeating/mongrel2,chickenkiller/mongrel2,jiffyjeff/mongrel2,krakensden/mongrel2,krakensden/mongrel2,elo80ka/mongrel2,musl/mongrel2,fanout/mongrel2,krakensden/mongrel2,fanout/mongrel2,pjkundert/mongrel2,musl/mongrel2,jasom/mongrel2,cpick/mongrel2,cpick/mongrel2,jdesgats/mongrel2,jablkopp/mongrel2,jasom/mongrel2,jdesgats/mongrel2,pjkundert/mongrel2