These changes allow manually overridden SRCDIR (current source
directory) and TOPDIR (top of source tree) to separate the
build directory from the source tree.

Signed-off-by: Gene Cumm <gene.cumm@gmail.com>
Signed-off-by: Nigel Croxon <nigel.croxon@hp.com>
Initialize Status before calling GrowBuffer()

Status must be initialized before calling GrowBuffer() as it may otherwise
 be uninitialized or set to EFI_BUFFER_TOO_SMALL by other functions.

Signed-off-by: Gene Cumm <gene.cumm@gmail.com>