XQuartz launching when packrat init

@jmcphers said the lock file might make it easier to reproduce this issue, so here it is:

PackratFormat: 1.4
PackratVersion: 0.4.7.1
RVersion: 3.3.0
Repos: CRAN=https://cran.rstudio.com/

Package: BH
Source: CRAN
Version: 1.60.0-2
Hash: be2967bcff307e561d9ba17faf03205c

Package: DBI
Source: CRAN
Version: 0.4-1
Hash: 6524d5c5d30ff74084ac028eeb19eb1b

Package: R6
Source: CRAN
Version: 2.1.2
Hash: c515e41c73294952cbb33ee1c1be5a2d

Package: Rcpp
Source: CRAN
Version: 0.12.5
Hash: 625a95cb4ef523a77ad02e140b715db6

Package: assertthat
Source: CRAN
Version: 0.1
Hash: 0afb92b59b02593c70ff8046700ba9d3

Package: base64enc
Source: CRAN
Version: 0.1-3
Hash: c590d29e555926af053055e23ee79efb

Package: bitops
Source: CRAN
Version: 1.0-6
Hash: 67d0775189fd0041d95abca618c5c07e

Package: caTools
Source: CRAN
Version: 1.17.1
Hash: 97cb6f6293cd18d17df77a6383cc6763
Requires: bitops

Package: digest
Source: CRAN
Version: 0.6.9
Hash: fd55d5a024f160fc001a5ece1e27782d

Package: dplyr
Source: github
Version: 0.4.3.9001
Hash: 4cccd1168d2bfb961cc8398dacee6eb7
Requires: BH, DBI, R6, Rcpp, assertthat, lazyeval, magrittr, tibble
GithubRepo: dplyr
GithubUsername: hadley
GithubRef: master
GithubSha1: b21fc8fa513d8488373f06e0097d18353b7e5e58

Package: evaluate
Source: CRAN
Version: 0.8
Hash: aac00bd789bac10970b50e3b7e0cab04
Requires: stringr

Package: formatR
Source: CRAN
Version: 1.2.1
Hash: 54c730c712edd6087972ecf99bf87c55

Package: highr
Source: CRAN
Version: 0.5.1
Hash: 114ef5abcf58bebbf6ac083b9cacbbd8

Package: htmltools
Source: CRAN
Version: 0.3
Hash: 7ccc01f4d22d73d0d9b0d2a7781e7ff6
Requires: Rcpp, digest

Package: jsonlite
Source: CRAN
Version: 0.9.21
Hash: 4715435f79ce983ec7e041f6be4742f4

Package: knitr
Source: CRAN
Version: 1.13
Hash: 8d686cbee88c93b735281a22b2ca59dd
Requires: digest, formatR, highr, yaml, markdown, stringr, evaluate

Package: lazyeval
Source: CRAN
Version: 0.2.0
Hash: 3d6e7608e65bbf5cb170dab1e3c9ed8b

Package: magrittr
Source: CRAN
Version: 1.5
Hash: bdc4d48c3135e8f3b399536ddf160df4

Package: markdown
Source: CRAN
Version: 0.7.7
Hash: fea2343a1119d61b0cc5c0a950d103a3
Requires: mime

Package: mime
Source: CRAN
Version: 0.4
Hash: b08c52dae92a0a11e64a4deea032ec33

Package: packrat
Source: CRAN
Version: 0.4.7-1
Hash: 16ca16d36eb18d1d16113606ecc5c400

Package: readxl
Source: CRAN
Version: 0.1.1
Hash: 92417d60a200a0f92fc8c4697105c3ff
Requires: Rcpp

Package: rmarkdown
Source: github
Version: 0.9.6.8
Hash: 0ef962f5004b2397ba9ec948ce42065b
Requires: base64enc, jsonlite, yaml, caTools, htmltools, evaluate, knitr
GithubRepo: rmarkdown
GithubUsername: rstudio
GithubRef: master
GithubSha1: a39fd8014269820f1e0e0a57d7e3805c8af27d01

Package: stringi
Source: CRAN
Version: 1.0-1
Hash: cf342bc407bd5daec77ed1009d5244e1

Package: stringr
Source: CRAN
Version: 1.0.0
Hash: 2676dd5f88890910962b733b0f9540e1
Requires: magrittr, stringi

Package: tibble
Source: CRAN
Version: 1.0
Hash: 135bebe37e899e9ebabcfdf74cb86ade
Requires: Rcpp, assertthat, lazyeval

Package: yaml
Source: CRAN
Version: 2.1.13
Hash: 4854ccabebc225e8a7309fb4a74980de

Start by reproducing the XQuartz launch during packrat initialization with the supplied lock file and R 3.3.0 environment. Trace the initialization path to identify why XQuartz launches, then verify that packrat init completes without launching it.