always close open file handles

Fixes #1619

vendor/clink.lua

@@ -210,8 +210,10 @@ end
 local function get_git_status()
     local file = io.popen("git --no-optional-locks status --porcelain 2>nul")
     for line in file:lines() do
+        file:close()
         return false
     end
+    file:close()
 
     return true
 end
@@ -221,9 +223,12 @@ end
 -- @return {bool}
 ---
 local function get_hg_status()
-    for line in io.popen("hg status -0"):lines() do
+    local file = io.popen("hg status -0")
+    for line in file:lines() do
+        file:close()
         return false
     end
+    file:close()
 
     return true
 end
@@ -232,10 +237,13 @@ end
 -- Get the status of working dir
 -- @return {bool}
 ---
-local function get_svn_status()
+function get_svn_status()
-    for line in io.popen("svn status -q"):lines() do
+    local file = io.popen("svn status -q")
+    for line in file:lines() do
+        file:close()
         return false
     end
+    file:close()
 
     return true
 end