title: dplyr 0.3.0.2 rename() idiom unstable when reshape package is loaded
body: <pre><code>sessionInfo()
  # R version 3.1.1 (2014-07-10)
  # Platform: x86_64-apple-darwin10.8.0 (64-bit)
  # 
  # attached base packages:
  #   [1] stats     graphics  grDevices utils     datasets  methods   base     
  # 
  # other attached packages:
  #   [1] dplyr_0.3.0.2
  # 
  # loaded via a namespace (and not attached):
  #   [1] assertthat_0.1 DBI_0.3.1      lazyeval_0.1.9 magrittr_1.0.1 parallel_3.1.1 Rcpp_0.11.3   
  # [7] tools_3.1.1  
  </code></pre>
  
  <h3>when only dplyr 0.3.0.2 was loaded, the default rename idiom worked.</h3>
  
  <pre><code>packageVersion("dplyr")
  # [1] ‘0.3.0.2’
  iris[1:10,] %&gt;% rename(petal_length = Petal.Length)
  #    Sepal.Length Sepal.Width petal_length Petal.Width Species
  # 1           5.1         3.5          1.4         0.2  setosa
  # 2           4.9         3.0          1.4         0.2  setosa
  </code></pre>
  
  <h3>when library(reshape) was loaded, the idiom did not seem to work</h3>
  
  <pre><code># other attached packages:
  #   [1] reshape_0.8.5 dplyr_0.3.0.2
  # 
  # loaded via a namespace (and not attached):
  #   [1] assertthat_0.1   chron_2.3-45     data.table_1.9.5 DBI_0.3.1        lazyeval_0.1.9  
  # [6] magrittr_1.0.1   parallel_3.1.1   plyr_1.8.1       Rcpp_0.11.3      reshape2_1.4    
  # [11] stringr_0.6.2    tidyr_0.1        tools_3.1.1     
  
  iris[1:10,] %&gt;% rename(petal_length = Petal.Length)
  # Error in rename(`iris[1:10, ]`, petal_length = Petal.Length) : 
  #   unused argument (petal_length = Petal.Length)
  </code></pre>
  
  <h3>and need to resort to the code below</h3>
  
  <pre><code>iris[1:10,] %&gt;% rename(c("Petal.Length" = "petal_length"))
  #    Sepal.Length Sepal.Width petal_length Petal.Width Species
  # 1           5.1         3.5          1.4         0.2  setosa
  # 2           4.9         3.0          1.4         0.2  setosa
  </code></pre>
  
  <p>Is this a bug?</p>