Add utils function for handling subprocess.

cloudcontrol/node/utils.py

+import subprocess
+
+
 def and_(iter):
     """Do an and logic condition over the iterable element.
 
@@ -8,3 +11,17 @@ def and_(iter):
             return False
 
     return True
+
+
+def subproc_call(args, stdin=None):
+    """
+    :param args: arguments for subprocess call
+    :param stdin: stdin data as string
+    """
+    proc = subprocess.Popen(args, bufsize=4096, stdin=subprocess.PIPE,
+                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    result, _ = proc.communicate(stdin)
+    if proc.returncode != 0:
+        raise subprocess.CalledProcessError(proc.returncode,
+                                            'Error while executing command')
+    return result