Repait module.desc

- a handful of modules had an unused *requires* key in module.desc;
  this is probably from previous intentions around
  prerequisites-testing. Since the settings were empty anyway,
  they have been removed.
- [unpackfs] Compacted the way *requiredModules* list is written

src/modules/displaymanager/module.desc

@@ -2,5 +2,4 @@
 type:       "job"
 name:       "displaymanager"
 interface:  "python"
-requires:   []
 script:     "main.py"

src/modules/hwclock/module.desc

@@ -2,6 +2,5 @@
 type:       "job"
 name:       "hwclock"
 interface:  "python"
-requires:   []
 script:     "main.py"
 noconfig:   true

src/modules/networkcfg/module.desc

@@ -2,6 +2,5 @@
 type:       "job"
 name:       "networkcfg"
 interface:  "python"
-requires:   []
 script:     "main.py"
 noconfig:   true

src/modules/services-systemd/module.desc

@@ -2,5 +2,4 @@
 type:       "job"
 name:       "services-systemd"
 interface:  "python"
-requires:   []
 script:     "main.py"

src/modules/unpackfs/module.desc

@@ -4,5 +4,4 @@ type:       "job"
 name:       "unpackfs"
 interface:  "python"
 script:     "main.py"
-requiredModules:
- - mount
+requiredModules: [ mount ]