cgi: Fix compatibility with Python 2.6

CGI interface should be compatible with Python 2.6 to provide packages
for CentOS 6. This commit fixes issues caused by str.format() calls
which use empty (i.e. "{}") format strings by using operator % for
string formatting in all the tables.

Change-Id: I98fabd454d955ba964386d82aab287a2e35a273c
rpm: Make packages register services properly

This commit:
* Modifies rpm packages to add mfs user in post-install scripts for
  master, metalogger and chunkserver packages.
* Adds support for SysV (used in CentOS 6 and RHEL 7)
* Adds support for systemd (used in CentOS 7 and RHEL 7)
* Modifies daemons to make 'mfsXXXXXX stop' succeed when the process
  is stopped and updates test_exit_status to verify if the stop command
  succeeds in such scenarios

Change-Id: I7569fe8afac49c4e886489bdfb404bd03d40293a
rpm: Add a script which builds RPM packages

This commit adds a script which properly creates both .rpm as well as
.src.rpm packages from an existing git working copy.

This scripts makes all the hacks in the %prep phase unneeded, so this
commit also removes them. Just a simple %setup should work now.

Change-Id: I74e65d3c23b57fbafb295930f4fbac1ed0df8492