Ubuntu Install: fix install script & update README

This patch implements a fix for the installation on the Ubuntu OS.
It removes the quotes from the NAME of the os-release file. These quotes
are not present in all distros, such as Fedora where they are absent.

A typo is fixed, that concatenated the cpu count with the -c argument.

Also, this patch fixes a typo in the README file concerning the py script
to call to run the dependencies installations.

Change-Id: I71c76a29ed1daee2b8ee133a20918d42a0156432
Tuleap: #451

README.md

@@ -14,7 +14,7 @@ Ring installer uses python3. Please make sure it is installed before running it.
 
 Build and install all the dependencies:
 
-    ./ring-build --dependencies
+    ./make-ring.py --dependencies
 
 #### Linux
     Your distro package manager will be used.

make-ring.py

@@ -141,7 +141,7 @@ def run_install(args):
         install_args += " -c client-macosx"
         execute_script(["CONFIGURE_FLAGS='--without-dbus' ./scripts/install.sh " + install_args])
     else:
-        install_args += '-c client-gnome'
+        install_args += ' -c client-gnome'
         execute_script(["./scripts/install.sh " + install_args])
 
 
@@ -286,7 +286,7 @@ def choose_distribution():
             for line in f:
                 k,v = line.split("=")
                 if k.strip() == 'NAME':
-                    return v.strip()
+                    return v.strip().replace('"','')
     elif system == "darwin":
         return 'OSX'