Do not manually convert bool to integer

Clippy emits:

 warning: boolean to int conversion using if

As suggested use `usize::from`

Author: tcharding

src/miniscript/astelem.rs

@@ -775,7 +775,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Terminal<Pk, Ctx> {
             Terminal::Check(ref sub) => sub.node.script_size() + 1,
             Terminal::DupIf(ref sub) => sub.node.script_size() + 3,
             Terminal::Verify(ref sub) => {
-                sub.node.script_size() + if sub.ext.has_free_verify { 0 } else { 1 }
+                sub.node.script_size() + usize::from(!sub.ext.has_free_verify)
             }
             Terminal::NonZero(ref sub) => sub.node.script_size() + 4,
             Terminal::ZeroNotEqual(ref sub) => sub.node.script_size() + 1,

src/miniscript/types/extra_props.rs

@@ -443,9 +443,9 @@ impl Property for ExtData {
     }
 
     fn cast_verify(self) -> Result<Self, ErrorKind> {
-        let verify_cost = if self.has_free_verify { 0 } else { 1 };
+        let verify_cost = usize::from(!self.has_free_verify);
         Ok(ExtData {
-            pk_cost: self.pk_cost + if self.has_free_verify { 0 } else { 1 },
+            pk_cost: self.pk_cost + usize::from(!self.has_free_verify),
             has_free_verify: false,
             ops: OpLimits::new(verify_cost + self.ops.count, self.ops.sat, None),
             stack_elem_count_sat: self.stack_elem_count_sat,

src/miniscript/types/malleability.rs

@@ -309,7 +309,7 @@ impl Property for Malleability {
         let mut all_are_non_malleable = true;
         for i in 0..n {
             let subtype = sub_ck(i)?;
-            safe_count += if subtype.safe { 1 } else { 0 };
+            safe_count += usize::from(subtype.safe);
             all_are_dissat_unique &= subtype.dissat == Dissat::Unique;
             all_are_non_malleable &= subtype.non_malleable;
         }