Renamed roles private variables to adhere to code style. (#1507)

contracts/access/roles/CapperRole.sol

@@ -8,7 +8,7 @@ contract CapperRole {
   event CapperAdded(address indexed account);
   event CapperRemoved(address indexed account);
 
-  Roles.Role private cappers;
+  Roles.Role private _cappers;
 
   constructor() internal {
     _addCapper(msg.sender);
@@ -20,7 +20,7 @@ contract CapperRole {
   }
 
   function isCapper(address account) public view returns (bool) {
-    return cappers.has(account);
+    return _cappers.has(account);
   }
 
   function addCapper(address account) public onlyCapper {
@@ -32,12 +32,12 @@ contract CapperRole {
   }
 
   function _addCapper(address account) internal {
-    cappers.add(account);
+    _cappers.add(account);
     emit CapperAdded(account);
   }
 
   function _removeCapper(address account) internal {
-    cappers.remove(account);
+    _cappers.remove(account);
     emit CapperRemoved(account);
   }
 }

contracts/access/roles/MinterRole.sol

@@ -8,7 +8,7 @@ contract MinterRole {
   event MinterAdded(address indexed account);
   event MinterRemoved(address indexed account);
 
-  Roles.Role private minters;
+  Roles.Role private _minters;
 
   constructor() internal {
     _addMinter(msg.sender);
@@ -20,7 +20,7 @@ contract MinterRole {
   }
 
   function isMinter(address account) public view returns (bool) {
-    return minters.has(account);
+    return _minters.has(account);
   }
 
   function addMinter(address account) public onlyMinter {
@@ -32,12 +32,12 @@ contract MinterRole {
   }
 
   function _addMinter(address account) internal {
-    minters.add(account);
+    _minters.add(account);
     emit MinterAdded(account);
   }
 
   function _removeMinter(address account) internal {
-    minters.remove(account);
+    _minters.remove(account);
     emit MinterRemoved(account);
   }
 }

contracts/access/roles/PauserRole.sol

@@ -8,7 +8,7 @@ contract PauserRole {
   event PauserAdded(address indexed account);
   event PauserRemoved(address indexed account);
 
-  Roles.Role private pausers;
+  Roles.Role private _pausers;
 
   constructor() internal {
     _addPauser(msg.sender);
@@ -20,7 +20,7 @@ contract PauserRole {
   }
 
   function isPauser(address account) public view returns (bool) {
-    return pausers.has(account);
+    return _pausers.has(account);
   }
 
   function addPauser(address account) public onlyPauser {
@@ -32,12 +32,12 @@ contract PauserRole {
   }
 
   function _addPauser(address account) internal {
-    pausers.add(account);
+    _pausers.add(account);
     emit PauserAdded(account);
   }
 
   function _removePauser(address account) internal {
-    pausers.remove(account);
+    _pausers.remove(account);
     emit PauserRemoved(account);
   }
 }

contracts/access/roles/SignerRole.sol

@@ -8,7 +8,7 @@ contract SignerRole {
   event SignerAdded(address indexed account);
   event SignerRemoved(address indexed account);
 
-  Roles.Role private signers;
+  Roles.Role private _signers;
 
   constructor() internal {
     _addSigner(msg.sender);
@@ -20,7 +20,7 @@ contract SignerRole {
   }
 
   function isSigner(address account) public view returns (bool) {
-    return signers.has(account);
+    return _signers.has(account);
   }
 
   function addSigner(address account) public onlySigner {
@@ -32,12 +32,12 @@ contract SignerRole {
   }
 
   function _addSigner(address account) internal {
-    signers.add(account);
+    _signers.add(account);
     emit SignerAdded(account);
   }
 
   function _removeSigner(address account) internal {
-    signers.remove(account);
+    _signers.remove(account);
     emit SignerRemoved(account);
   }
 }