Skip shell functions when parsing env

`getEnvFromShell` function calls `env` command through shell to get all
defined environment variable. However `env` also returns the shell
function defined with their whole code written on multiple lines.

Such shell function definitions were not properly handled by
`getEnvFromShell` which led to the following kind of error messages
(seen for instance when running a terminal package in Atom):

  bash: module: line 1: syntax error: unexpected end of file
  bash: error importing function definition for `BASH_FUNC_module'

With this change `getEnvFromShell` now skips shell function definition
to guarantee only environment variables are recorded and a sane `result`
array is returned.

Fixes atom#20389
Fixes atom#17369
Fixes atom#13451
Fixes blueimp/atom-open-terminal-here#27
Fixes blueimp/atom-open-terminal-here#18
Fixes bus-stop/Termination#101
Fixes bus-stop/terminus#24
Fixes platformio/platformio-atom-ide-terminal#120
Fixes platformio/platformio-atom-ide-terminal#293
Fixes AtomLinter/linter-pylint#243
Fixes AtomLinter/linter-flake8#643
Fixes AtomLinter/linter-flake8#165
Fixes AtomLinter/linter-flake8#422
Fixes AtomLinter/linter-puppet-lint#68
Fixes autocomplete-python/autocomplete-python#347

src/update-process-env.js

@@ -121,13 +121,22 @@ async function getEnvFromShell(env) {
   }
 
   let result = {};
+  let skip = false;
   for (let line of stdout.split('\n')) {
-    if (line.includes('=')) {
+    // start of shell function definition: skip full definition
+    if (line.includes('=() {')) {
+      skip = true;
+    }
+    if (!skip && line.includes('=')) {
       let components = line.split('=');
       let key = components.shift();
       let value = components.join('=');
       result[key] = value;
     }
+    // end of shell function definition
+    if (line === '}') {
+      skip = false;
+    }
   }
   return result;
 }