File copy issues on retrieve

[kevinohara80]

When files are being copied from the tmp directory to the src directory, you get unlinking errors when the file tries to overwrite an existing copy. This seems to be some sort of a race condition where the directory is being unlinked after a file is being copied into that directory.

λ: dmc retrieve 'src/classes/TestUtil*'
[dmc] using org: l11.dev2 (default)
[dmc] matching types
[dmc] * matched type: ApexClass
[dmc] retrieve status: Pending
[dmc] unzipping to tmp dir: /Users/kevinohara/.dmc/.tmp
[dmc] extracting zip
[dmc] merging files to src
[dmc] * copying file: classes
[dmc] * copying file: classes/TestUtil.cls
[dmc] * copying file: classes/TestUtil.cls-meta.xml
[err] ENOENT, unlink '/Users/kevinohara/dev/l11/production/src/classes/TestUtil.cls'
[err] file copy errors
[err] [NOT OK]