Clear unused symbols warnings

Unused functions and variables are removed from the Nimble's source
code.

Resolves #680

src/nimblepkg/download.nim

@@ -10,13 +10,6 @@ type
   DownloadMethod* {.pure.} = enum
     git = "git", hg = "hg"
 
-proc getSpecificDir(meth: DownloadMethod): string =
-  case meth
-  of DownloadMethod.git:
-    ".git"
-  of DownloadMethod.hg:
-    ".hg"
-
 proc doCheckout(meth: DownloadMethod, downloadDir, branch: string) =
   case meth
   of DownloadMethod.git:
@@ -30,19 +23,6 @@ proc doCheckout(meth: DownloadMethod, downloadDir, branch: string) =
     cd downloadDir:
       doCmd("hg checkout " & branch)
 
-proc doPull(meth: DownloadMethod, downloadDir: string) =
-  case meth
-  of DownloadMethod.git:
-    doCheckout(meth, downloadDir, "")
-    cd downloadDir:
-      doCmd("git pull")
-      if existsFile(".gitmodules"):
-        doCmd("git submodule update")
-  of DownloadMethod.hg:
-    doCheckout(meth, downloadDir, "default")
-    cd downloadDir:
-      doCmd("hg pull")
-
 proc doClone(meth: DownloadMethod, url, downloadDir: string, branch = "",
              onlyTip = true) =
   case meth

src/nimblepkg/nimscriptsupport.nim

@@ -375,8 +375,6 @@ proc execScript(scriptName: string, flags: Flags, options: Options): PSym =
                "more info."
     raiseNimbleError(msg, hint)
 
-  let pkgName = scriptName.splitFile.name
-
   # Ensure that "nimblepkg/nimscriptapi" is in the PATH.
   block:
     let t = getNimbleUserTempDir() / "nimblecache"
@@ -692,11 +690,6 @@ proc execHook*(scriptName, actionName: string, before: bool,
 
   cleanup()
 
-proc getNimScriptCommand(): string =
-  when declared(NimCompilerApiVersion):
-    let conf = graph.config
-  nimCommand()
-
 proc setNimScriptCommand(command: string) =
   when declared(NimCompilerApiVersion):
     let conf = graph.config

src/nimblepkg/packageinfo.nim

@@ -310,7 +310,6 @@ proc findNimbleFile*(dir: string; error: bool): string =
 
   if result.splitFile.ext == ".nimble-link":
     # Return the path of the real .nimble file.
-    let nimbleLinkPath = result
     result = readNimbleLink(result).nimbleFilePath
     if not fileExists(result):
       let msg = "The .nimble-link file is pointing to a missing file: " & result