Bug found in repos_upload()

Hi,

I've resolved my issue in Issue 257. When calling repos_upload('myLib','local_cran'), packrat puts the value of 'local_cran' in my repos to the Repository field of the DESCRIPTION file of myLib. For instance, if my repos is like:

CRAN CRANextra
"https://cran.rstudio.com/" "http://www.stats.ox.ac.uk/pub/RWin"
local_cran
"file:///D:/local_cran"

Then the DESCRIPTION file in the myLib in the local_cran is something like:
...
Repository: file:///D:/local_cran
...

The related code is

repo <- if (isNameOfRepo) repos[[to]] else to

in line 113 of cranlike-repositories.R

However, in the function inferPackageRecord (line 299 of pkg.R):
else if (!is.null(df$Repository) && df$Repository %in% names(repos))
{
# It's a package from a custom CRAN-like repo!
...

It only checks if the value of Repository is in the names of repos, so what it actually wants is Repository: local_cran

Now I have to manually change my DESCRIPTION file to go through the snapshot(). Thanks.

Start in cranlike-repositories.R at line 113, where repos_upload() selects the Repository value, and compare it with inferPackageRecord in pkg.R at line 299. Reproduce the local_cran case and verify that the generated DESCRIPTION retains the repository name so snapshot() can recognize the package without manual editing.