plugin: set reset more while installing binaries

Reset 'more' while installing binaries. Set it back to its original
value before returning. If necessary, Vim will only prompt the user for
more once, at the end of the process instead of multiple times during.

plugin/go.vim

@@ -136,6 +136,9 @@ function! s:GoInstallBinaries(updateBinaries, ...)
     let l:platform = 'windows'
   endif
 
+  let l:oldmore = &more
+  let &more = 0
+
   for [l:binary, l:pkg] in items(l:packages)
     let l:importPath = l:pkg[0]
 
@@ -230,6 +233,8 @@ function! s:GoInstallBinaries(updateBinaries, ...)
   else
     call go#util#EchoInfo('installing finished!')
   endif
+
+  let &more = l:oldmore
 endfunction
 
 " CheckBinaries checks if the necessary binaries to install the Go tool