remove m_keepConn from fastcgi

It looks like the only thing we do with `m_keepConn` is leak the connection. Is there something better we should be doing with it? If not, lets kill all this.

Closes #1690

Reviewed By: @simpkins

Differential Revision: D1154770
Fix slow memory leaks in File subclasses

Fix slow memory leaks in File subclasses (Socket, MemFile, UrlFile)

Closes #1672
Closes #1774

Reviewed By: @markw65

Differential Revision: D1166202

Pulled By: @scannell
make date_create match zend for null input

Reviewed By: @jdelong

Differential Revision: D1154703