Remove explicit from PEFile::Signature copy constructor.
Remove explicit from PEFile::Signature copy constructor.

The lack of an implicit copy constructor was causing VS2013 compile time issues.

BUG=
R=sebmarchand@chromium.org

Review URL: https://codereview.appspot.com/59050043

git-svn-id: db59699583a60be9a535cd09cdc9132301867226@2014 15e8cca8-e42c-11de-a347-f34a4f72eb7d

wangming28/syzygy,sebmarchand/syzygy,ericmckean/syzygy,wangming28/syzygy,google/syzygy,pombreda/syzygy,google/syzygy,pombreda/syzygy,sebmarchand/syzygy,ericmckean/syzygy,ericmckean/syzygy,google/syzygy,Eloston/syzygy,pombreda/syzygy,wangming28/syzygy,sebmarchand/syzygy,supriyantomaftuh/syzygy,ericmckean/syzygy,sebmarchand/syzygy,pombreda/syzygy,sebmarchand/syzygy,google/syzygy,pombreda/syzygy,supriyantomaftuh/syzygy,ericmckean/syzygy,Eloston/syzygy,wangming28/syzygy,supriyantomaftuh/syzygy,supriyantomaftuh/syzygy